ETC CH1798

HIGH SPEED Modem and FAX FAMILY
CH2056
CH1799
CH1798
CH1794
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INTRODUCTION
FEATURES
The CH2056, CH1799, CH1798 and CH1794 (HS Modem
Family) are industrial grade high speed modem modules.
Each HS Modem product supports a range of modem
standards and speeds from 300bps to 14,400bps, 28,800bps,
33,600bps or 56,000bps. By using built in compression
algorithms the operating speed can be expanded to the
maximum DTE rate of 57.6kps for the CH1794, 115.2Kbps
for the CH1798/CH1799 and 230.4kbps for the CH2056. A
choice of error correcting schemes is available including MNP
10 for cellular telephone applications. The HS Modem family
supports Send and Receive Fax. The CH1799LL operates
exclusively on non-voltage bearing leased line.
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The HS Modem family is pin compatible with Cermetek’s low
cost CH1786 V.22bis, 2400bps modem family. Each module
in the HS Modem family is a self-contained modem and is
FCC Part 68 approved and Canadian DOT approveable.
These ultra small modules are designed for PCB throughhole mounting and are 1.35” x 1.38” x 0.58” in size. The HS
Modem family requires only two external interfaces: a CCITT
V.24 serial interface that can be routed directly to a UART,
and a Tip and Ring interface which goes directly to an RJ11C Jack for the PSTN line connection. The HS Modem can
be controlled with industry standard AT commands and is
compatible with available industry communication software.
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V.90 / 56,000bps
V.34bis / 33,600bps
V.34 / 28,800bps
V.32bis / 14,400bps
Supports V.90, V.34bis, V.34, V.32bis, V.32, V.22bis,
V.22A/B, V.23, V.21, Bell 212A and 103
CH2056 supports V.80 Synchronous operation
Error correcting: V.42 LAMP, MNP 2-4 and MNP 10
Data Compression: V.42bis and MNP 5
MNP10 Data throughput enhancement for cellular
operation
DTE serial interface with speeds up to 230.4kbps
(CH2056), 115.2kbps (CH1799/CH1798) or 57.6kbps
(CH1794)
Automatic baud rate adaptability utilizing speed sensing,
flow control and data buffers
Send & Receive Fax Class 1, Group 3 supported
Serial V.24, 5 volt interface
NVRAM directory and stored profiles
AT Command structure, with extensions
Built-in DAA with 1500 VAC RMS isolation 2122V peak
surge protection
UL 1950 and CSA C22.2 950 Recognized
Leased Line version available CH1799LL
FCC part 68 Approved/DOT CSA CS-03 Part I
Approveable
+5 Volt operation with zero power option
Small size: 1.35” x 1.38” x 0.61” (nominal)
Pin compatible with low speed/low cost CH1786
Figure 1. Function Block Diagram of HS Modem Family.
DESCRIPTION OF FUNCTIONAL BLOCKS AND
DISCUSSION OF BASIC OPERATIONS
Figure 1 contains a functional block drawing of the HS
Modem family of products. Each HS Modem product
consists of a serial interface buffer, modulator/demodulator,
modem controller with error correction and data compression,
non-volatile RAM and a DAA.
Serial Host Interface Buffer.
The HS Modem utilizes a serial V.24 EIA 232-E 5V interface
to control the modem. The HS Modem products can
communicate over the serial interface with the Data Terminal
Equipment (DTE) at a fixed speed regardless of the carrier
line modulation speed (DCE) of the PSTN modem
connection. This eliminates the need to have the DTE step
up or step down in speed based on the incoming or out-going
PSTN communication data rate. Hence, the DTE can train
the CH2056, to say 56kbps, and talk to a slower incoming
data connection at say, 2400bps without changing host
speed. Conversely, the host DTE trained at 14.4kbps can
also communicate with the modems at higher speeds, say
28.8kbps.
This is accomplished by invoking internal
automatic data flow control. The HS Modem family has a
resident buffer to allow for this auto baud operation.
Non-Volatile RAM (NVRAM).
NVRAM can store two user-customized configurations. The
AT&Wn command will store the active modem configuration
in one of two NVRAM locations as selected by an n of 0 or 1.
The AT&Yn command selects one of the stored modem
configurations to be automatically recalled and made active
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upon reset or power up. The ATZn command immediately
recalls and activates a stored configuration. See Tables 7A
and 7B for storable S-Registers and Commands.
The NVRAM can save up to four telephone numbers, with up
to 36 digits or modifiers in each telephone number. The
AT&Zn=s command will store s, the telephone number dial
string. The ATDS=n command will cause the modem to dial
one of the four stored telephone numbers. The NVRAM
storage location for the four telephone numbers is selected
by an n of 0, 1, 2, or 3.
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Documt No. 607-0003 Revision G (05/00)
Telephone Line Interface or DAA.
High performance modems are extremely sensitive to DAA
(Data Access Arrangement) performance. The difference
between a good modem and a fair one is in the DAA
performance. The HS Modem family includes a unique low
distortion DAA designed for optimal performance over all
PSTN line conditions thereby achieving the most reliable and
best performance PSTN connections.
The HS Modem family is designed to meet North American
telephone standards as set by FCC Part 68 (USA) and CSA
CS-03 Part I (Canada). Among the more critical parameters,
the PSTN line interface is designed to meet 1500 VAC RMS
isolation and provide 2122V peak surge protection.
Consequently, the HS Modem family of products satisfies
U.S. and Canadian requirements, and will meet other
international approval agency requirements that specify these
levels of isolation.
Pins 1 and 2 function as both input and output connections to
the PSTN.
To maximize field reliability in hostile
environments, for Canadian approval, for UL compliance, and
also optionally for FCC Part 15 compliance, these two pins
must be routed through an external network such as that
described in Figure 6A and in Cermetek Application Note #
126.
Each HS Modem product comes with FCC Part 68 approval
and is shipped from the factory with an FCC label indicating
registration number and ringer equivalent. This label should
be prominently displayed on the end product. With the
exception of the U.S., most countries (including Canada)
require submission of the final product or system containing
the HS Modem to the appropriate governing regulatory
agency for approval. Typically this is accomplished by
submitting the final end product to an independent test house
or consultant for evaluation. The test house/consultant then
forwards the test results and applicable documents to the
regulatory agency. Contact Cermetek for a list of suggested
consultants.
Modulation/Demodulation/ Error Correcting and Data
Compression.
These functions are provided by an industry standard modem
chip set which has been adapted for use with the HS Modem
Family. The Modulation/Demodulation scheme supports the
industry modem standards listed below.
Bell 103
Bell 212A
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SUPPORTED FEATURES
AT Command Set.
The HS Modem supports the AT Command set with
extensions and can operate with industry standard
communication software.
The AT commands are
compatible with TR302.2/88-08006.
Serial Host Interface.
The HS Modem Family operates in asynchronous mode and
supports a 5V, RS232- like interface called V.24 (EIA-232E). The HS Modem supports a full RS-232C/V.24 serial
interface. Signal levels are TTL rather than RS-232C level
compatible, which allows direct connection of the HS
Modem to the host’s UART without level translating circuitry.
See Table 3 for a complete set of pin descriptions.
The modem is controlled by sending serial commands over
TXD and by monitoring serial status messages returned on
RXD. All other serial interface lines may be utilized for the
convenience of a particular application but are not required
by the modem. Unused outputs from the HS Modem should
be left unconnected. Unused inputs should be tied to the
proper logic level. See Table 3.
Speaker Interface.
The SPK output reflects the receiver analog input and
provides a signal that can be used to monitor call progress.
The SPK signal can drive a 300 ohm load directly.
Typically, the SPK signal is input into an audio power
amplifier and the amplifier, in turn, drives the speaker coil.
The speaker is activated with the Atm command. The
speaker volume is adjusted using the ATLn command,
where n is 0, 1, 2, or 3. Increasing numbers correspond to
higher volume. Figure 3 indicates one method of driving an
external 8 ohm speaker.
Zero Power Mode.
If an application calls for zero power during standby periods,
the power may be switched off using external circuitry and
then reapplied when the HS Modem’s RI pin becomes
active. The HS Modem can thus be powered down to zero.
The pins of the HS Modem will be in an undefined state
when power is switched off. This must be taken into
consideration to assure that no unwanted signals are
presented to the HS Modem during power down.
The HS Modem supports V.42 LAMP, MNP 2-4, MNP 10
error correcting protocols. The CH1794 uses MNP5 data
compression techniques and the CH1798/9/CH2056 uses
V.42bis data compression, allowing data transmission rates
of up to a maximum of 57.6kbps/115.2kbps/230.4kbps,
respectively. These high DTE data rates are supported by
the HS Modem serial interface via its auto baud capability.
Note that the maximum speed attained is limited by the
maximum speed available from the DTE.
supports
Since a modem communicates data serially and most host
products handle data in a parallel format, a UART is needed
to make parallel-to-serial and serial-to-parallel translations.
Referring to Figure 2, the controller activates the relay
switch, supplying power (+5V) to the HS Modem. In this
configuration, the ring signal is used to “wake up” the HS
Modem when the HS Modem is in the power down state.
CCITT V.22
CCITT V.22bis
CCITT V.32
CCITT V.32bis
CCITT V.34
CCITT V.34bis
CCITT V.90
The resident Modulator/Demodulator
equalization and forward error correction.
CONNECTING TO THE HOST UART
line
Power Supply.
The HS Modem module is a complex set of sensitive
subsystems. During the course of normal operation, the HS
Modem decodes analog signals from the telephone line that
are in the millivolt range. Steps must be taken by the user
to guarantee that power supply noise on all supply lines,
including ground, does not exceed 25 mV peak to peak. If
necessary, use dedicated power and ground planes. Failure
to provide such operating conditions could cause the HS
Modem to malfunction or to function erratically.
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Document No. 607-0003 Revision G (05/00)
The HS Modem Family requires a single +5V ±5% supply. It
is recommended that bypass capacitors be placed on the
power supply as close to the HS Modem’s supply input pins
as practical. It is recommended that a 10 µF or greater
tantalum capacitor in parallel with a 0.1 µF ceramic capacitor
be used. The user must also provide shielding from nearby
sources of EMI, such as relays, motors and other power
supplies.
flow control causes an overall throughput data rate penalty.
Table 1. Data Formats Recognized by HS Modem
Family.
Figure 2. Zero Power Operation.
Parity
Data Length
(No. of Bits)
None
Odd
Even
None
Odd
Even
7
7
7
8
8
8
No. of
Stop Bits
Character
Length
(No. of Bits)
2
1
1
1
1
1
10
10
10
10
11*
11*
*11 bit characters are sensed, but the parity bits are
stripped off during data transmission in Normal and
Error Correction modes.
Table 2. HS Modem Auto Configuration Based on DTE
Configuration.
DTE Configuration
HS Modem Configuration
7 mark
7 space
8 mark
8 space
Automatic Speed/Format Sensing.
The HS Modem supports both Command and Data modes of
operation.
7 none
8 none
8 none
8 even.
Figure 3. Speaker Control Circuit.
The HS Modem can automatically determine the speed and
format of the data sent from the DTE over the serial interface;
and can sense the following broad range of speeds:
CH1794
300, 600, 1200, 2400, 4800, 7200, 9600, 12000,
14400, 19200, 38400, and 57600bps
CH1798/9 300, 600, 1200, 2400, 4800, 7200, 9600, 12000,
14400, 16800, 19200, 21600, 24000, 26400,
28800, 38400, 57600 and 115200bps
CH2056 300, 600, 1200, 2400, 4800, 7200, 9600, 12000,
14400, 16800, 19200, 21600, 24000, 26400,
28800, 38400, 57600, 115200 and 230400bps
The data formats in Table 1 are recognized by the HS
Modem family of products.
The HS Modem can sense data with mark or space parity
and configures itself as described in Table 2.
The HS Modem is trained to a selected speed with an AT
[CR] training sequence. Thus, the DTE to modem serial
interface speed can be set independent of the DCE or line
carrier connecting speed (with minor restrictions, see the AT
+ MS command). This allows greater flexibility when
selecting DCE line carrier modulation speed thereby affording
the user with optimum data throughput performance. To
maximize effective modem data throughput speed, the DTE
to modem serial interface speed should be set to the highest
speed available without invoking the use of the HS Modem’s
built-in flow control.
Although flow control facilitates
communication with higher speed modes by the DTE, use of
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Voice/Tone Injection Port.
The HS Modem Family provides pin T1 to allow the user to
share the PSTN line interface associated with the modem
for voice and DTMF applications. Figure 5 contains a
schematic indicating one possible configuration for
voice/tone utilization.
All HS Modem products are designed with pin T1 coupled
directly to the internal DAA. When using the HS Modem in
data mode, T1 should float and be disconnected from any
potential signal because any signal on T1 during data
operation will affect the HS Modem’s output. If T1 is being
asserted from another application, use a relay or zero
impedance switch to disconnect T1 when in data mode.
Referring to Figure 5, use the variable resistor (POT) to set
required speaker volume.
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Document No. 607-0003 Revision G (05/00)
To maintain FCC compliance, frequencies transmitted while
in voice mode should be between 300Hz and 3000Hz.
When voice and data are both being used, and the RXA and
TXA pins are active, it is typical for voice communication to
precede data communication. In this case, the following
commands should be used to configure the HS Modem to
allow for full utilization of the Voice/Tone injection feature.
These commands disable auto-answer and eliminate hangup due to lack of carrier signal.
1.
2.
3.
Enter: ATS0=0 [CR]
Enter: ATS7=255 [CR]
Enter: ATS10=255 [CR]
The following command sequences illustrate implementation
of common voice/tone port applications.
1.
To answer a voice call:
(a) Enter: ATH1 [CR]
(b) Switch local voice source into RXA and TXA
(c) Begin voice conversation.
2.
To switch to data mode, switch local voice source from
RXA and TXA:
(a) At the Originate Modem, enter: ATX1 [CR]
(b) At the Answer modem, enter: ATA [CR]
3.
To disconnect (hang-up) a voice call or data call:
(a) Return to control mode by Entering: +++
(b) Enter: ATH [CR]
4.
To place a voice call using the HS Modem DTMF
facilities:
(a) Enter: ATDT(Tele)#;[CR]
(b) Then switch to local voice source
MODEM CONTROL
The HS Modem may be controlled by sending serial ASCII
command sequences. The commands are sent to the modem
serially on the TXD pin. After execution of a received
command, the modem returns a serial status message that
can be read on pin RXD.
This message indicates
command completion status. Refer to Tables 5A, 5B and
5C for a complete list of status messages.
MODEM STATES
The HS Modem can be in either command mode or data
mode. When the modem is idle, it is in command mode by
default and will recognize commands.
When data
transmission is in progress, the HS Modem is in the data
mode state and will not recognize commands. To force the
HS Modem to recognize commands, the host must send an
“escape sequence” to the HS Modem forcing it out of data
mode and into command mode.
The escape sequence consists of a “guard time” (a period
where no characters are sent to the modem), followed by 3
escape characters, followed by another guard time. At
power-up, the guard time is set to 1 second minimum, and
the escape character is set as “+.” These two parameters
can be modified via registers S2 and S12, respectively.
The HS Modem will stay off-hook with its carrier on after the
escape sequence is received and it returns an OK status
message when it is ready to accept commands. The HS
Modem can be put into data mode by issuing the command
ATO [CR].
THE COMMAND FORMAT
Typical commands consist of three elements:
1. The attention sequence,
2. The commands themselves and
3. A terminating carriage return.
WARNING: The HS Modem family of products has been
FCC Part 68 approved as data/FAX modems. Utilization
of the Voice/Tone Port requires further registration. The
FCC requires that the entire system, including the HS
Modem and the handset or DTMF transceiver, adhere to
Part 68 rules.
Figure 4. HS Modem Family Application Diagram.
2000 Cermetek Microelectronics, Inc.
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Document No. 607-0003 Revision G (05/00)
AT [commands] [CR].
Where: [AT] represents attention sequence.
[commands] represents command strings.
[CR] represents carriage return (ASCII 13 or HEX 0D).
When entering commands to the modem, the backspace
character-control-H (ASCII 8 or HEX 08) can be used to edit
mistakes. “AT” and “A/” may not be edited however. Multiple
commands may be placed in the command line. A command
line may be as long as 40 characters, excluding the letters
AT. By way of example, the command below instructs the
HS Modem to configure itself to not echo characters when in
command mode (E0) and then put itself in answer mode (A).
Enter: AT[CR]
Where: A and T may be either upper or lower case but
must be the same case.
[CR] represents carriage return
The “AT” sequence is referred to as an attention sequence.
The HS Modem will respond with one of the following status
messages, depending on whether it is optioned for
abbreviated or English status messages.
Result: 0[CR] (Abbreviated form)
Result: [CR][LF][OK][CR][LF] (English form)
Where: [CR] represents carriage return (ASCII 13 or
HEX 0D).
[LF] represents line feed (ASCII 10 or HEX 0A).
Enter: ATE0A[CR]
AT Command Set.
The available command set is divided into four types of
commands : dial modifiers, basic commands, ampersand and
percent commands. Refer to the complete list in Tables 6A
and 6B.
INITIALIZING THE MODEM
Before commands may be sent to the HS Modem, the
modem must be initialized. This consists of two events:
1. Modem Reset. This is accomplished by applying a
hardware reset pulse to pin RST or by switching the
power off and then back on.
2. Initial Modem Training. The modem must be trained to
the host DTE speed and parity (odd, even, mark, space
or none). These activities are briefly described below.
Reset.
Upon applying power to the HS Modem, the HS Modem
automatically generates an internal reset pulse. The user
can also reset the modem externally by applying a high-going
reset pulse to the RST pin for at least 10ms after the +5V
power supply has stabilized. Delay sending commands to
HS Modem for 900ms after reset has been initiated to allow
the HS Modem time to properly reconfigure.
On power up, or when reset is initiated either by command
(ATZ) or by the RST pin, the modem will reconfigure to its
default state with the line carrier modulation speed set to:
1.
2.
3.
4.
14.4kbps for the CH1794
28.8kbps for the CH1798
33.6kbps for the CH1799
56.0kbps for the CH2056
If desired, any speed, error correction, or data compression
method available on the HS Modem can be locked in, using
the AT\Nn and/ or AT+MS commands.
Training the Modem.
Each modem must be trained to match the host DTE speed
and parity so that it is able to recognize serial asynchronous
commands sent to it by the DTE.
The DTE must retrain the modem each time a reset pulse is
applied on RST or after a RESET serial command has been
issued.
Modem Training Command Sequence.
The HS Modem is trained by sending it the following
sequence:
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The modem is now in idle mode and is ready to accept
commands.
An alternate attention sequence “A/” may be sent which
behaves much like the AT sequence except that it causes
the previously entered command specified with an AT prefix
to be executed. When given, it must be in upper case
ASCII. No carriage return is needed.
STATUS MESSAGES AND RESULT CODES
A result code is issued by the HS Modem to the DTE for all
commands executed by the HS Modem, except dialing
commands. Further, various activities on the PSTN are also
signaled to the DTE by the HS Modem.
All result codes have either a terse, short form version
(which is identified by a number followed by a [CR]) or a
verbose long form English-like message version (which is
preceded and terminated with a [CR] and line feed).
The user may suppress certain subsets of the non-extended
result codes. This is accomplished by selecting subsets of
the result code set using the ATXn command, where n=0, 1,
2, 3. Optionally, the user may specify an extended set of
result codes (codes above 35) by setting Register S95. See
the detailed description of result codes in Table 5A, Table
5B and Table 5C.
All AT commands, other than dialing commands, will be
responded to with either an OK (short form result code 0) if
the command is valid or accepted, or with an ERROR (result
code 4) if the command is not recognized. The detail
contained in the error result codes signaled to the DTE
depends on the level of message suppression employed by
the user. As can be seen from Tables 5A, 5B and 5C,
specifying X4 allows the HS Modem to utilize the entire
range of non-extended messages, whereas X0 suppresses
all but the very basic result codes. Most of the result codes
allowed under X1, X2 and X3 are considered call progress
status codes and, in practice, are suppressed except for the
case of debugging activities. It is recommended that the
non-extended result codes be used in all cases.
It should be noted that the default connect result codes 9-20
indicate DTE connection speed, not Carrier Line DCE
speed. Hence, a CH1794 will connect at a maximum speed
of 19.2kbps (result code 16). The CH1798 and CH1799 will
connect at a maximum DTE speed of 38.4kbps (result code
17) and the CH2056 will connect at a maximum speed of
57.6kbps (result code 18) unless the DTE is forced to a
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Document No. 607-0003 Revision G (05/00)
Table 3. HS Modem Family Pin Descriptions
2000 Cermetek Microelectronics, Inc.
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Document No. 607-0003 Revision G (05/00)
higher speed by selection of data compression. In this case,
the maximum DTE to modem speed is 230.4kbps (result
code 20).
Extensions to the basic result code set can be specified by
Register S95, which allows for the use of result codes 40 –
64, 165 - 194.
Note: Result codes 53 - 64 are supported by the CH1798,
CH1799 and CH2056. Result codes 165 – 194 are only
supported by the CH2056. To obtain a detailed status report
for a given modem communication configuration, use the
AT\V1 command. Executing this command at setup will
cause the modem to connect and return a message on line
consisting of <DTE speed> <modulation> <error protocol>
<line speed of connection>.
LEASED LINE OPTION
The CH1799LL is a leased line version of the CH1799.
Whereas the CH1799 requires an active voltage bearing or
wet PSTN line for normal operations (typically, 48VDC onhook line voltage), the CH1799LL is designed to operate over
a non-voltage bearing or dry line.
The CH1799LL will only operate properly on a dry line.
Damage will occur if used on a wet line. The CH1799LL
does not support ring detect but does support off-hook
control. Refer to Cermetek Application Note #116 for
examples and instructions to establish a connection over a
leased dry line wire pair. Note that the length of the leased
line is limited to 20,000 feet. Use PSTN line protection as
recommended in Figure 6B and in Cermetek Application Note
# 126. Follow all applicable requirements for FCC Part 68
compliance. The User is responsible to ensure that FCC Part
68 compliance is maintained.
As an alternative, the CH1799 will operate on a leased line if
the line is made wet by application of a DC voltage. Refer to
Cermetek Application Note #114.
WARNING: Operation of the CH1799LL on a standard
PSTN line will damage the CH1799LL and void its
warranty. Further, operation of the CH1799LL on a dry
line without using proper current limiting circuitry as
outlined in Cermetek Application Note #126 may cause
damage to the CH1799LL and will also void its warranty.
Table 4. Pin Comparison of CH1786 and HS Modem
Family.
PIN
CH1786
HS Modem FAMILY
1
RING
RING
2
TIP
TIP
3
RXA
T1
4
TXA
NC
5
SPK
SPK
6
NC
NC
7
NC
NC
8
SLEEP
OPEN*
9
NC
NC
10
TXD
TXD
11
RXD
RXD
12
V/D
OPEN*
13
DTR
DTR
14
DSR
DSR
15
RI
RI
16
CTS (FX only)
CTS
17
DCD
DCD
18
HS
NC*
19
Vcc
Vcc
20
GND
GND
21
RST
RST
22
NC
RST
Notes:
1.
* Indicates a difference between the CH1786 and the
2.
3.
HS Modem. The HS Modem may be directly
substituted for the CH1786 except in applications
where pins 8, 12 or 18 are used.
NC signifies Not Connected.
Effective 31 March 2000, the HS Modem will no
longer support the HS indication function.
Therefore, pin 18 should be a No Connect in all
applications.
Pause During Dialing.
When placing a call from an office with a telephone
connected to a PBX, it may be necessary to dial an access
code (usually the digit 9) to get an outside line. Inserting a
comma in the telephone number commands the modem to
pause for a specific length of time. The factory default
pause time is 2 seconds.
Example: Dial 9, pause, dial number.
Enter:
ATDT9, T1234567
AT COMMAND APPLICATIONS
Dialing A Phone Number.
The Dial command takes the form Dn, where n is a string of
characters. In the simplest form, n will be only the digits of
the phone number to be dialed.
Example: Dial Number.
Enter:
AT D1234567
In response to this command, the HS Modem dials the
telephone number “123-4567” and then waits for a carrier
from the distant modem. If no carrier is detected within a
given time (the default time is 30 seconds), the HS Modem
automatically releases the line and sends a NO CARRIER
result code. If a carrier is detected, the HS Modem gives a
CONNECT result code and goes on-line, permitting
communication with the distant modem.
Multiple commas may be used for a greater delay time.
Touch Tone and Pulse Dialing.
The modem can use DTMF (touch-tones) “T,” or dial pulses
“P” when dialing a telephone number. If the dial command
does not specify which type to use, the modem defaults to
the type last specified. The power-on default value is T.
Example: Pulse dial 9, pause, touch-tone dial number
Enter:
ATDP9, T1234567
Redial Last Number.
Use A/, the repeat command, to redial the last telephone
number dialed when a busy signal is received.
Example: Touch-tone dial 9, pause, dial number, return
for command.
Enter:
ATDP9, T1234567;
The Dial Command may also be issued without a telephone
number. ATD causes the modem to pick up the telephone
line without dialing a number.
2000 Cermetek Microelectronics, Inc.
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Document No. 607-0003 Revision G (05/00)
Figure 5. Schematic Illustrating Implementation of Voice Injection Feature.
Table 5A Summary of Non-Extended Result Codes.
Table 5B. CH1798/9 Extended Result Codes.
Note: 1. An ”x” in a column indicates that the message (either the long form if verbose, or the value only for short form) will be
generated when that particular value of ”n” (shown at the top of the column) has been selected by the use of ATXn. A numeral
indicates which less explicit message (verbose or short form) will be output for that X option.
2000 Cermetek Microelectronics, Inc.
Page 8
Document No. 607-0003 Revision G (05/00)
Table 5C. CH2056 Extended Result Codes.
5.
6.
7.
8.
9.
RJ-11C jack must be 0.1 inch spacing or greater to one
another and 0.2 inch spacing or greater to all other
traces. The traces should have a nominal width of
0.020 inches or greater.
The RING and TIP PCB traces should be as short as
possible and oriented to prevent coupling other high
speed or high frequency signals present on the host
circuit PCB.
No additional circuitry other than that shown in Figure 7
may be connected between the modem module and the
RJ-11C Jack.
Doing so will invalidate the FCC
approval.
The HS Modem, the RJ-11 Jack, the interfacing circuitry
and all PCB traces in between, must be contained on a
PCB with a 94 V-0 flammability rating.
The supplied FCC registration label must be applied
visibly on the outside of the product.
The product’s User Manual must provide the user with
instructions for connection and use as recommended in
the FCC Registration Section below.
CANADIAN APPROVALS
The HS Modem family is approveable for use by DOT to
CSA CS-03 Part I. However, per Canadian procedures,
approval can only be granted after the HS Modem has been
installed into the end product. Typically, Canadian approval
is obtained by submitting the final end product to an
independent test house or consultant for evaluation. The
test house/consultant then forwards the test results and
applicable documents to the regulatory agency. Cermetek
offers a list of consult-ants to assist with this process.
HS MODEM HANDLING AND ASSEMBLY
RECOMMEN-DATIONS
The HS Modem contains static-sensitive components and
should only be handled by personnel and in areas that are
properly protected against static discharge.
Return to Command State.
The modem can be forced to reenter the command state after
dialing (without hanging up) by ending the dial command with
a semi-colon. This is useful when using the modem as an
auto dialer.
Automatic Answering.
S0=0*
DO NOT ANSWER TELEPHONE
S0=1-254
ANSWER ON RING 1 TO RING 254
S0=255
ANSWER ON RING 255
*When S0 is set to 0, the modem will not auto-answer.
PHONE LINE CONNECTION GUIDELINES
1.
2.
3.
4.
The HS Modem must be mounted in the final assembly
such that it is isolated from exposure to any hazardous
voltages within the assembly. Adequate separation and
restraint of cables and cords must be provided.
The circuitry from the HS Modem to the telephone line
interface must be provided in wiring that carries no other
circuitry other than that specifically allowed in the FCC
rules (such as A and A1 leads).
Connection to phone line should be made through an RJ11C jack.
PCB traces from the modem’s RING and TIP pins to the
2000 Cermetek Microelectronics, Inc.
There are two mounting techniques that are recommended
for physically connecting the HS Modem to a PCB:
1. Direct soldering
2. Sockets.
Direct Soldering.
The HS Modem may be wave soldered onto a circuit card.
All HS Modem products are hermetically sealed and will not
be harmed by industry standard wave soldering processes.
Socketing.
The socketing approach to mounting eliminates cleaning
and desoldering concerns. When the socket is used, it must
make a solid connection to all pins. Failure to do so will
cause unreliable or intermittent operation. Also, steps
should be taken to assure that the module remains tightly
seated in the socket after the end product is shipped.
Cermetek recommends socket CES-150-01-T-S by Samtec,
50 pin strip socket.
FCC REGISTRATION
All products in the HS Modem family are registered with the
FCC (except the CH1799LL) under Part 68. To maintain the
validity of the registration, you must serve notice to the end
user of the product of several restrictions the FCC places on
the modem and its use.
Page 9
Document No. 607-0003 Revision G (05/00)
COMMAND
A/
A
B0
B1
C1
Dn
E0
E1
H0
H1
L0
L1
L2
L3
M0
M1
M2
M3
N0
N1
O0
O1
Q0
Q1
Sn
Sn?
Sn=v
V0
V1
W0
W1
W2
Table 6A. Summary of Basic AT Commands.
FUNCTION
COMMAND
FUNCTION
Re-execute command
Go off-hook and attempt to answer call
Select V.22 connection at 1200bps
Select Bell 212A connection at 1200bps
Return OK message
Dial modifier
P
Pulse Dial
T
Touch Tone Dial
W
Wait for Dial Tone
;
Return to Idle State
@
Wait for Quiet Answer
Command
!
Flash Hook
,
Pause
0-9/ABCD Dial Digits/
Characters & wait for credit
card dial tone
∧
Toggles calling tone
L
Redial last number
*
Star digit – tone dialing
S=n
Dial the number and store in
directory. N 0 to 3.
Turn off command echo
Turn on command echo
Initiate a hang-up sequence
If on-hook, go off-hook and enter command
mode
Set low speaker volume
Set low speaker volume
Set medium speaker volume
Set high speaker volume
Turn Speaker off
Turn speaker on during hand shaking and
turn speaker off while receiving carrier
Turn speaker on during hand shaking and
while receiving carrier
Turn speaker off during dialing and receiving
carrier and turn speaker on during answering
X0
X1
X2
X3
X4
Y0
Y1
Z0
Z1
&C0
&C1
&D0
&D1
&D2
&/D3
Report basic call progress result codes, i.e. OK,
CONNECT< RING, NO CARRIER (also for busy,
if enabled, and dial tone not detected), NO
ANSWER and ERROR
Report basic call progress result codes, i.e. OK,
CONNECT< RING, NO CARRIER (also for busy,
if enabled, and dial tone not detected), NO
ANSWER and ERROR
Report basic call progress result codes, i.e. OK,
CONNECT< RING, NO CARRIER (also for busy,
if enabled, and dial tone not detected), NO
ANSWER and ERROR
Report basic call progress result codes, i.e. OK,
CONNECT< RING, NO CARRIER (also for busy,
if enabled, and dial tone not detected), NO
ANSWER and ERROR
Report basic call progress result codes, i.e. OK,
CONNECT< RING, NO CARRIER (also for busy,
if enabled, and dial tone not detected), NO
ANSWER and ERROR
Disable long space disconnect before on-hook
Enable long space disconnect before on-hook
Restore stored profile 0 after warm reset
Restore stored profile 1 after warm reset
Force RLSD active regardless of the carrier state
Allow RLSD to follow the carrier state
Interpret DTR On to OFF transition per & Qn:
&Q0, &Q5, &Q7
The modem ignores DTR
Interpret DTR On to OFF transition per & Qn:
&Q0, &Q5, &Q6
Interpret DTR On to OFF transition per & Qn:
&Q0, &Q5, &Q6
Interpret DTR On to OFF transition per & Qn:
&Q0, &Q5, &Q6
The modem performs soft reset.
Turn off auto-mode detection
Turn on auto-mode detection
Go on-line
Go on-line and initiate a retrain sequence
Allow result codes to DTE
Inhibit result codes to DTE
Select S-Register as default
Return the value of S-Register n
Set default S-Register to value v
Report short form (terse) result codes
Report long form (verbose) result codes
Report DTE speed in EC model
Report line speed, EC protocol and DTE
speed
Report DCE speed in EC mode
2000 Cermetek Microelectronics, Inc.
Page 10
Document No. 607-0003 Revision G (05/00)
COMMAND
&F0
&F1
&G0
&G1
&G2
&K0
&K3
&K4
&K5
&K6
Kn
\K0,2,4
\K1
\K3
\K5
\K0,1
\K2,3
\K4,5
\K0,1
\K2,3
\K4,5
\N0
\N1
\N2
\N3
\N4
\N5
\V0
\V1
+MS
%C0
%C1
%C2
%C3
\A0
\A1
\A2
\A3
\Bn
&M0
&P0
Table 6B. Summary of Basic AT Commands (Continued).
FUNCTION
COMMAND
FUNCTION
Restore factory configuration 0
Restore factory configuration 1
Disable guard tone
Disable guard tone
Enable 1800 Hz guard tone
Disable DTE/ DCE flow control
Enable RTS/ CTS DTE/DCE flow control
Enable XON/XOFF DTE/DCE flow control
Enable transparent XON/XOFF flow control
Enable both RTS/CTS and XON/XOFF flow
control
CONTROLS BREAK HANDLING DURING
THREE STATES
When modem receives a break from
the DTE:
Enter on-line command mode, no break
sent to the remote modem
Clear buffers and send break to remote
modem
Send break to remote modem
immediately
Send break to remote modem in
sequence with transmitted data
When modem receives \b in on-line
command state:
Clear buffers and send break to remote
modem
Send break to remote modem
Send break to remote modem in
sequence with transmitted data
&P1
&P2
&P3
&Q0
&Q5
&Q6
&T0
&T1
&T2
&T3
&T4
&T5
&T6
&T7
&T8
&V
&W0
&W1
&Y0
&Y1
&Zn=x
%E0
%E1
%E2
Set 10 pps pulse dial with 33%/67%
make/break
Set 20 pps pulse dial with 39%/61%
make/break
Set 20 pps pulse dial with 33%/ 67% make/
break
Select direct asynchronous mode
Modem negotiates an error corrected link
Select asynchronous operation in normal
mode
Terminate any test in progress
Initiate local analog loopback
Return ERROR result code
Initiate local digital loopback
Allow remote digital loopback
Disallow remote digital loopback request
Request an RDL without self-test
Request an RDL with self-test
Initiate local analog loop with self-test
Display current configurations
Store the active profile in NVRAM profile 0
Store the active profile in NVRAM profile 1
Recall stored profile 0 upon power up
Recall stored profile 1 upon power up
Store dial string x (to 34) to location n (0-3)
Disable line quality monitor and auto retrain
Enable line quality monitor and auto retrain
Enable line quality monitor and fallback
When modem receives break from
remote modem:
Clear data buffers and send break to DTE
Send a break immediately to DTE
Send a break with received data to DTE
Select normal speed buffered mode
Select direct mode
elect reliable link mode
Select auto reliable mode
Force LAPM mode
Force MNP mode
Connect messages are controlled by the
command settings X, W, and S95
Connect messages are displayed in the
single line format
Select modulation
ERROR CORRECTING COMMANDS
Disable data compression
Enable MNP 5 data compression
Enable V.42bis data compression
Enable both V.42.bis and MNP5
compression
Set maximum block size in MNP to 64
Set maximum block size in MNP to 128
Set maximum block size in MNP to 192
Set maximum block size in MNP to 256
Send break of n x 100 ms
Select direct asynchronous mode
Set 10 pps pulse dial with 39%/61% make/
break
2000 Cermetek Microelectronics, Inc.
MNP10 COMMANDS
-K0
Disable MNP 10 extended services
-K1
Disable MNP 10 extended services
-K2
Disable MNP 10 extended services
FAX CLASS 1
+FCLASS=n
+FAE=n
+FRH=n
+FRM=n
+FRS=n
+FTH=n
+FTM=n
+FTS=n
Page 11
Service Class
Data/fax auto answer
Receive data with HDLC framing
Receive data
Receive silence
Transmit data with HDLC framing
Transmit data
Stop transmission and wait
Document No. 607-0003 Revision G (05/00)
Table 7. S-Register Summary.
Register
S0
S1
S2
S3
S4
S5
S6
S7
S8
S9
S10
S11
S12
S13
S14
S15
S16
S17
S18
S21
S22
S23
S24
S25
Function
Rings to Auto-Answer
Ring Counter
Escape Character
Carriage Return Character
Line Feed Character
Backspace Character
Wait Time for Dial Tone
Wait Time for Carrier
Pause Time for Dial Delay Modifier
Carrier Detect Response Time
Carrier Loss Disconnect Time
DTMF Tone Duration
Escape Prompt Delay
Reserved
General Bit Mapped Options Status
Reserved
Test Mode Bit Mapped Options Status (&T)
Reserved
Test Timer
V.24/General Bit Mapped Options Status
Speaker/Results Bit Mapped Options Status
General Bit Mapped Options Status
Reserved
Delay to DTR Off
Range
0-255
0-255
0-255
0-127
0-127
0-255
2-255
1-255
0-255
1-255
1-255
50-255
0-255
----------0-255
--------0-255
S26
S27
S28
S30
S31
S32
S33
S34-S35
S36
S37
S38
S39
S40
S41
S42-S45
S46
S48
S82
S86
S95
RTS-to-CTS Delay
General Bit Mapped Options Status
General Bit Mapped Options Status
Disconnect Inactivity Timer
General Bit Mapped Options Status
XON Character
XOFF Character
Reserved
LAPM Failure control
Line Connection Speed
Delay before Forced Hang up
Flow Control bit Mapped Options Status
General Bit Mapped Options Status
General Bit Mapped Options Status
Reserved
Data Compression Control
V.42 Negotiation Control
LAPM Break Control
Call Failure Reason Code
Result Code Messages Control
0-255
----0-255
--0-255
0-255
------0-255
--------------0-255
---
2000 Cermetek Microelectronics, Inc.
Page 12
Units
Rings
Rings
ASCII
ASCII
ASCII
ASCII
seconds
seconds
seconds
0.1seconds
0.1seconds
0.001sec
0.02sec
----------seconds
--------seconds or
0.01second
0.01second
----10 seconds
--ASC11
ASC11
------seconds
-------------------
Saved
*
*
*
*
*
*
*
----------*
-----------
Default
0
0
43
13
10
8
2
50
2
6
14
95
50
--138 (8Ah)
--0
--0
52 (34h)
117 (75h)
62 (3Dh)
--5
-------------
1
73
0
0
94
17
19
*
*
7
0
20
3
104 (68h)
195 (C3h)
--138
7
128 (40h)
--0
*
*
*
*
*
*
(49h)
(C2h)
(11h)
(13h)
---
Document No. 607-0003 Revision G (05/00)
In addition to restriction notification, the FCC requires that
Cermetek make all repairs to all products in the HS Modem
family. If repairs are necessary after installation of the HS
Modem and the end product has been delivered to the end
user, the end product must be returned to the end product
supplier where the HS Modem can be removed and then
forwarded to Cermetek repair. The following notice is
recommended and should be included in the end product’s
user manual.
complaint with the FCC. Contact your local telephone
service provider if you have any questions about your phone
line.
FOR YOUR USER’S MANUAL
DEFAULT STATUS, PERFORMANCE AND SPECS
The part 68 rules require the following (or equivalent) be
provided to the end user of the equipment containing a
DAA:
Prior to delivery , Cermetek installs into each HS Modem the
following the Default Configuration Profile:
Type of Service: The (insert end product name) is
designed to be used on standard device telephone lines. It
connects to the telephone line by means of a standard jack
called the USOC RJ-11C (or USOC RJ45S). Connection to
telephone-company-provided coin service (central office
implemented systems) is prohibited. Connection to party
lines service is subject to state tariffs.
Changes in Attestation Procedure for Plugs and Jacks:
(Name of applicant) attests that the network interface plugs
or jacks used on this equipment comply with and will
continue to comply with the mechanical requirements
specified in Part 68, Sub-part F, specifically the
dimensions, tolerances and metallic plating requirements.
The compliance of these connectors will be assured by
purchase specifications and incoming inspection.
Documentation of such specifications and/or inspections
will be provided by the FCC within 30 days of their request
for the same.
Telephone Company Procedure:
The goal of the
telephone company is to provide you with the best service
it can. In order to do this, it may occasionally be necessary
for them to make changes in their equipment, operations or
procedures. If these changes might effect your service or
the operation of your equipment, the telephone company
will give you notice, in writing, to allow you to make any
changes necessary to maintain uninterrupted service.
In certain circumstances, it may be necessary for the
telephone company to request information from you
concerning the equipment which you have connected to
your telephone line. Upon request of the telephone
company, provide the FCC registration number and the
ringer equivalence number (REN); both of these items are
listed on the equipment label. The sum of all of the REN’s
on your telephone lines should be less than five in order to
assure proper service from the telephone company. In
some cases, a sum of five may not be useable on a given
line. Consult your telephone provider.
If Problems Arise: If any of your telephone equipment is
not operating properly, you should immediately remove it
from your telephone line, as it may cause harm to the
telephone network. If the telephone company notes a
problem, they may temporarily discontinue service. When
practical, they will notify you in advance of this
disconnection. If advance notice is not feasible, you will be
notified as soon as possible.
When you are notified, you will be given the opportunity to
correct the problem and informed of your right to a file a
2000 Cermetek Microelectronics, Inc.
In the event repairs are ever needed on the (insert your
product name), they should be performed by (insert your
company name) or an authorized representative of (insert
your company name). For information contact: (insert your
company address).
Default Connect Speeds are 14,400bps, 28,800bps, 33,600bps and
56,000bps for CH1794, CH1798, CH1799 and CH2056 respectively
Serial port data rate auto baud enabled
Bell 212A operation at 1200bps
Parity - none
Auto answer disabled
Command echo ON
All result codes enabled – except \REL codes
Wait for dial tone before dialing – 2 seconds
Dials with touch-tone (T)
Detects busy signal (ATX4)
Full word result codes - non-extended
Pulse dial make/break ratio = 39/61- 10 pps
Test timer set to 0 seconds, test modes disabled
Inactivity timer set to 0 minutes
CTS always active
DSR is ignored
DCD is ignored
RTS to CTS delay - .01 seconds
DTR always active - hangs up after transition
Long space disconnect disabled
Speaker enabled but off when receiving carrier
Speaker volume set to low
Local modem will not grant RDL request from remote modem
Guard tones disabled
Minimum DTR pulse width = .05 seconds
Ring count – 00
Escape code character = 43 (+)
Flash to on hook = 70 ms
Auto speed detection enabled
DTE connect speed, connect messages
Back space character = 08 (BS)Carriage return character = 13 (CR)
Line feed character = 10 (LF)
Duration of wait for dial tone = 2 seconds
Duration of wait for carrier after dialing = 50 seconds
Carrier detect response time = 0.6 seconds
Escape code guard time = 1 second
Length of use after comma = 2.0 seconds
Last carrier to hang up delay = 1.4 seconds
DTMF interdigit delay = .095 seconds
Auto sync address or address detection = 0
Connection detected at DTE – Highest speed 38,400bps
Auto retrain enabled - 30 seconds attempt
MNP error correction mode can be negotiated (&Q5)
MNP - non-extended service selected
MNP error correction block size is 128 characters selected
Data compression -negotiation enabled
Transmit break length is 0.3 seconds
All breaks are transmitted in sequence with data
Serial port flow control enabled = RTS/CTS
XON/XOFF flow control characters selected
NOTE: Upon power-up the HS Modem will recall user profile 0
which may override some of the above Factory Defaults. If
desired the user may, at their option, save the factory defaults
in user profile 0.
Page 13
Document No. 607-0003 Revision G (05/00)
Figure 6A. PSTN Line Interface for all HS Modems except CH1799LL.
Figure 6B. PSTN Line Interface for CH1799LL only.
2000 Cermetek Microelectronics, Inc.
Page 14
Document No. 607-0003 Revision G (05/00)
Table 8. HS Modem Electrical Specifications.
Table 9. HS Modem Electrical Specifications.
2000 Cermetek Microelectronics, Inc.
Page 15
Document No. 607-0003 Revision G (05/00)
Table 10. Analog Characteristics.
Name
Type
SPK
O(DF)
Characteristic
Value
Minimum Load
Maximum Capacitive Load
Output Impedance
Output Voltage
D.C. Offset
300Ω
0.01µ
10Ω
2.5 + 1.6V
<20mV
Table 11. Summary HS Modem Family of Products.
Model
Summary of Features
Operating Temperature
CH1794
CH1794ET
Full Function, 14.4kbps, FCC Part 68 Approved, UL1950 Listed
Full Function, 14.4kbps, FCC Part 68 Approved, UL1950 Listed
0° C to +70°C
-40° C to +85°C
CH1798
CH1798ET
Full Function, 28.8kbps, FCC Part 68 Approved, UL1950 Listed
Full Function, 28.8kbps, FCC Part 68 Approved, UL1950 Listed
0° C to +70°C
-40° C to +85°C
CH1799
CH1799ET
CH1799LL
Full Function, 33.6kbps, FCC Part 68 Approved, UL1950 Listed
Full Function, 33.6kbps, FCC Part 68 Approved, UL1950 Listed
Full Function, 33.6kbps, Leased Line, FCC Part 68 Approved
0° C to +70°C
-40° C to +85°C
0° C to 70°C
CH2056
CH2056ET
Full Function, 56.0kbps, FCC Part 68 Approved, UL1950 Listed
Full Function, 56.0kbps, FCC Part 68 Approved, UL1950 Listed
0° C to +70°C
-40° C to +85°C
Figure 7. Physical Dimensions and Pin Functions.
Cermetek reserves the right to make changes in specifications at any time and without notice. The information furnished by
Cermetek in this publication is believed to be accurate and reliable. However, no responsibility is assumed by Cermetek for its
use, or for any infringements of patents or other rights of third parties resulting from its use. No license is granted under any
patents or patent rights of Cermetek.
Printed in U.S.A
406 TASMAN DRIVE | SUNNYVALE CA 94089 | LOCAL: 408-752-5000 | TOLL FREE: 1-800-882-6271 | FAX: 408-752-5004
WEB SITE: http://www.cermetek.com | EMAIL: sales@cermetek.com
2000 Cermetek Microelectronics, Inc.
Page 16
Document No. 607-0003 Revision G (05/00)