CML Semiconductor Products
PRODUCT INFORMATION
CM1481
Non-Predictive Selcall Module
Obsolete Product
‘For Information Only’
Applications
Selcall in Two-W
ay Radio
o-Wa
Alarm Systems
Remote Contr
ol/Switc
hing
Control/Switc
ol/Switching
‘SECURE’ Contr
ol and Switc
hing
Control
Switching
Industrial Contr
ol
Control
Automatic User Identity
★‘N’-TONE SELCALL ENCODING & NON-PREDICTIVE DECODING +
★
GROUP CALLING
CM1481
Operating
and
Pr
ogramming
Programming
Man
ual
Manual
Features
★ Encoding and Non-Predictive
All-T
one Decoding
All-Tone
OUP-Call
★ All-System GR
GROUP-Call
★ Transponding and ANI
-Air “Stun and Release” and
★ Over
Over-Air
“Re-Configuration”
w-P
ower Requirement
★ Lo
Low-P
w-Po
(4.0mA @ 6v to 26v D
.C. [typ])
D.C.
★ CCIR, EEA and ZVEI Tonesets
★ Simple
Simple,, Serial Configuration
★ Multiple Coded Audio Alerts
acility
★ Remote Reset F
Facility
★ PTT Time-Out Timer
★ Simple Radio Interface
kout
★ PTT Loc
Lock
The CM1481 Non-Predictive Selcall Module
Table of Contents
Introduction to The CM1481
Summary of Standard Functions and Features
Installation Instructions
Power Requirements
Handling Precautions
Alert Audio Levels
Radio Interface
Circuit Diagram
PCB Layout
Configuration
Configuration Menu
Error and Status Messages
Receive Call Operation
Transmit Call Operation
LED Call Memory
LED Drive
Automatic REPEAT-Tone
Timed Mute Reset
Audio Alerts
PTT Lockout
Single or Dual Button Operation
Automatic Number Identification (ANI)
Tx Timeout and Warning
N OTONE Timer
Transponding
Input/Output Polarities
Lead-In Tone
Quiet/Open Modes
Lead-In Delay
Over-Air Functions
Power-Up 'Quiet'/'Open'
‘Muted’ Call Initiation
Security Checks
Example Over-Air Transactions
Pseudo-Random Number Information
Over-Air Tone Information
Hexadecimal Sequential Code
Operational Rules
Tone Allocations
International GROUP CALL
Non-International GROUP CALL
Specification
Ordering Information
2
3
3
4
4
4
4
5
6
7
8
10
11
12
12
12
12
13
13
13
13
14
14
15
15
15
15
16
16
16
17
17
17
18
19
19
20
21
21
22
22
22
23
24
Brief Introduction to The CM1481
‘Stun’, ‘Release’ and ‘Re-Configuration’ operations
are carried out using a secure authentication protocol
to prevent accidental or illegal transactions.
The unit may be muted by the base.
Under the control of its on-board µController,
operating from instructions written to it by a simple
menu-driven configuration operation from a basic 'PC'
type computer, the CM1481 can completely control
the workings of the radio's Rx and Tx audio
processes.
After Configuration the only operator inputs
required are Microphone/Handset, Volume and Selcall
Tx/Mute controls.
The CM1481 will detect and decode all incoming
tone information, controlling the radio functions whilst
providing the operator with various coded audio alerts
to indicate status and progress.
J1
/1
3
The CM1481 is a compact 5- or 6-Tone CCIR, EEA
and ZVEI selcall module with individual address
encoding, non-predictive all-tone decoding,
transponding and full, all-system GROUP Call and ANI
capabilities.
In addition to normal selcall facilities, the CM1481
offers, as standard, a range of over-air control facilities
to allow a base-station additional control when working
with remote units.
These added facilities are:
‘Stun’ and ‘Release’ - To allow the controller to
completely ‘freeze’ all module and parent radio audio
functions rendering it inoperative until ‘Released’. This
to counter theft, air misuse/abuse or non-payment of
fees.
‘Re-Configuration’ - To change module addresses
and modes via an over-air command. This to allow
unit participation in other user groups.
D
CM1481
X1
U
3
+
U
1
/1
-
J1
+
T
U
O
IN
-A
U
D
IO
SW
IT
C
H
U
2
U
4
Configuration Interface Connector
Fig.1 A Typical Configuration Setup
CM1481 - A Summary of Standard Functions and Features
Individual Addressing
Identification (ANI)
Extended Group & Data Tone
Facilities
Programmable Lead-In Tone
and Delay
Simple Radio Interface
Transponding Facility
Low-Power Requirement
(4.0mA typ)
Single or Dual Button Operation
Rapid Over-Air “ReConfiguration”
“Muted” Call Initiation
Tx (PTT) Time Out + Warning
Programmable I/O Polarities
Remote Reset
PTT (Busy) Lockout
Lead/Trail Automatic Number
CMOS Compatible Logic
Configuration by Menu-Driven
Software via a Serial ‘PC’ Link
CCIR, EEA and ZVEI
Toneset/Length Capabilities
HSC Signalling Control Features
Over-Air “Stun” & “Release”
Timed Mute Reset
Operators' Coded Call-Alert
Capability
3
Installation
Installation Instructions
The CM1481 is designed to be embodied physically within a mobile, portable or handheld transceiver to interface
electrically with Rx and Tx audio circuitry via the Radio Interface. The diagram below shows the input and output
system functions of the CM1481.
Before Installation it is recommended that this document is studied carefully.
Power Supply
(12)
(5)
(13)
PTT IN
Regulator
(4) QUIET/OPEN
(3)
Tx CALL
(2)
BUSY
(1)
CONFIG
(6)
V IN
GND
SIGNAL IN
Micro-Controller
Tx ON
(11)
MUTE CTRL (10)
Audio
Signalling
Processor
LED
(8)
TONE OUT
(9)
ALERT
(7)
EEPROM
Audio Switch
Fig.2 The Radio Interface
Method of Installation
Handling Precautions
Ensuring that there is sufficient room to introduce
the Radio Interface lead and the Configuration
Interface Connector, place the CM1481 into its
operating position using the double-sided sticky-pad
(supplied) on the discrete component side of the
module. Ensure that the module adheres firmly to its
mounting surface.
Consider the requirements for Single or Dual
Button operation.
Do not attempt to install the module into areas of
the radio where it may be subject to high RF fields.
Ensure that the CM1481 is well insulated from other
radio components.
It is recommended, at this stage, that some record
is formulated to identify the configuration state of the
module/radio pair.
The CM1481, which is supplied in an anti-static
package, contains CMOS devices. It is recommended
that to prevent damage, Electrostatic Discharge
Precautions are employed at all stages of any
production process involving this module.
Alert Audio Levels
If alert levels from the CM1481 are to be fed into
an external audio amplifier it is recommended that the
LINK is removed. Removal of the LINK will allow
connection to high-impedance loads.
LINK IN can drive an external loudspeaker.
LINK OUT can drive an external amplifier.
See layout diagrams, Figure 4, and Table 5 (Audio
Alert Descriptions).
Installation Dimensions
Power Requirements
CM1481 board size.
45mm x 22mm x 8mm.
The supply voltage requirement of the CM1481 is
between 6 and 26 volts d.c.
4
Installation ......
CM1481 Radio Interface
The table below shows the functions and interconnections of the CM1481 interface (J1) employed in both NORMAL
and CONFIGURATION modes.
Functions prefixed by a star (**) indicate configurable IN/OUT polarities. Consult the Configuration section of this
manual for Configuration Instructions and Configuration Interface Connector termination information.
Pin
Function
Normal Mode - to Radio
1
CONFIG
Configuration mode sense. When this pin is “High” the module WILL NOT enter the CONFIGURATION
mode, when “Low” the module WILL enter the CONFIGURATION mode on power-up.
2
* BUSY
Input from the radio squelch circuitry. A level here
indicates the presence of an RF carrier.
3
* Tx CALL
Input from the installation “Operation” momentaryaction switch to initiate a Selcall.
See "Single/Dual Button" Operation notes.
4
* QUIET/OPEN
5
* PTT IN
Input from the Mic. or peripheral PTT line.
The CM1481 controls the radio Tx function via
Tx On.
6
SIGNAL IN
Input for received Selcall tones from the radio
demodulator prior to squelch circuitry.
7
ALERT
Audible alerts output. Introduce into the radio's Rx
audio stage with due regard to any audio powersave
functions. This output can drive a loudspeaker directly.
8
* LED
Output drive to an LED indicator.
Connect an LED between this pin and GND.
9
TONE OUT
Selcall tone output. Introduce this output into the
radio Tx Audio path.
10
* MUTE CTRL
Connect to radio Rx Squelch circuitry so that when
this output is active Rx Audio is muted.
11
* Tx ON
Tx PTT Drive. When active this output will key the Tx.
12
GND
Signal Ground (-)
13
V IN
Positive Supply Voltage (+)
AUDIO SWITCH
Function
CLOCK
Input from the installation “Operation” momentary- DATA IN
action switch to control the radio mute state.
See "Single/Dual Button" Operation notes.
Configure Mode - to PC
The CLOCK signal generated by
the configuring PC is input here.
Data from the configuring PC to the
module is input here.
DATA OUT Data from the module to the
configuring PC is output here.
An on-board (Audio Signalling Processor) all-audio switch-path, accessible via on-board
solder-pads. This switch operates in co-ordination with the QUIET/OPEN function for use with all audio
signals. When 'Quiet' the switch is OFF, when 'Open' the switch is ON.
Table 1 CM1481 Radio Interface Functions
The position of Pin 1 is identified on Figure 4 (PCB Layout).
5
CM1481 Cir
cuit Dia
gram
Circuit
Diagram
AUDIO SWITCH
C2
GND
C3
X1
R2
24
44
41
12
11
10
9
8
7
6
5
GND
6
TCAP
U1
PA0
PA1
PA2
PA3
PA4
PA5
PA6
PA7
R7
R8
VPP
VSS
VDD
R11
13
14
15
16
17
19
20
21
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
R10
1
R9
PB0
PB1
PB2
PB3
PB4
PB5
PB6
PB7
PC7
PC6
PC5
PC4
PC3
PC2
PC1
PC0
PD0/RDI
PD1/TDO
PD2/MISO
PD3/MODI
PD4/SCK
PD5/SSN
TCMP
PD7
42
10
GND
13
XTALN
C4
VDD
SUMOP
SWSUMOP
SUMIN
6
LOGIN
15
VBIAS
14
TONE1
TONE2
CAL/CUES
SIBIAS
2
8
9
22
R14
20
21
16
17
18
R15
R27
R29
C 10
R28
LINK
C 11
R16
SCLK
VSS
7
3
C6
1
4
3
VDD
2
CS
VDD
DO
PE
U3
DI
PRE
VSS
SK
C 13
8
6
7
5
R6
22
GND
7
3
2
6
GND
GND
R18
VDD
GND
8
MUTE CTRL
PTT IN
LED
BUSY
Fig.3 CM1481 Circuit Diagram
VIN
SIGNAL IN
QUIET/OPEN
CONFIG
R31
R23
VDD
R30
R21
GND
V IN
C 12
ALERT
12
Tx ON
R20
DATA OUT
R26
GND
IRQN
RDATA
CLOCK
DATA IN
+
VIN
C8
R17
4
CSN
5
CDATA
23
CONFIGURE
CONFIG
11
C15
R5
R4
N/C1
N/C2
N/C3
U2
19
T2
VDD
AUDSWOP
RXAUDIN
R22
T1
XTAL
AUDSWIN
R12
4
RESETN
IRQN
OSC2
R24
R19
1
2
VDD
OSC1
R25
43
NORMAL
CONFIG
BUSY
Tx CALL
QUIET/OPEN
PTT IN
SIGNAL IN
ALERT
LED
TONE OUT
MUTE CTRL
Tx ON
GND
V IN
PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
R1
GND
CM1481 Cir
cuit Dia
gram
Circuit
Diagram
AUDIO SWITCH
C1
U4
VOUT
C 14
1
VDD
J1
V IN
GND
Tx ON
MUTE CTRL
TONE OUT
LED
ALERT
SIGNAL IN
PTT IN
QUIET/OPEN
CALL
BUSY
CONFIG
13
12
11
10
9
8
7
6
5
4
3
2
1
CM1481 PCB La
yout
Lay
J1/13
D
U1
If Alert Levels are to be
fed to an external audio
amplifier it is
recommended that the
LINK is removed so
that the ALERT output
can drive a high
impedance stage.
X1
+
U2
Note the position of the
on-board LINK on the
underside of the printed
circuit board.
LINK
J1/1
LINK IN will drive an
external loudspeaker.
LINK OUT will drive an
external amplifier
U3
U4
IN
OUT -AUDIO SWITCH
CM1481 Top View
Fig.4 PCB Layout
Component
Value
CM1481 Underside View
Component
Value
Component
Value
Component
U1
68HC705C8
R6
10.0kΩ
R20
47.0kΩ
C3
Value
0.1µF
U2
FX803LS
R7
10.0kΩ
R21
47.0kΩ
C4
0.1µF
U3
93CO6
R8
330Ω
R22
470kΩ
C5
not used
U4
LM2931-5
R9
47.0kΩ
R23
10.0kΩ
C6
0.1µF
T1
BCX19
R10
47.0kΩ
R24
10.0kΩ
C7
not used
T2
BCX19
R11
47.0kΩ
R25
10.0kΩ
C8
22.0pF
T3
BSR41
R12
2.2MΩ
R26
22.0Ω
C9
not used
R1
4.7MΩ
R13
not used
R27
2.0kΩ
C10
22.0µF
R2
100kΩ
R14
100kΩ
R28
LINK
C11
0.1µF
R3
not used
R15
100kΩ
R29
100kΩ
C12
0.1µF
R4
10.0kΩ
R16
47.0kΩ
R30
Note 1
C13
0.1µF
R5
10.0kΩ
R17
10.0kΩ
R31
Note 1
C14
0.1µF
R18
470kΩ
C1
39.0pF
C15
0.1µF
R19
470kΩ
C2
22.0pF
X1
4.0MHz
Table 2 Components List
Notes
1. Pads are made available on the CM1481 PCB for resistors R30 and R31 (not installed on this version) for future
hardware upgrades.
2. The pads to the audio switch are available for use with system audio. This switch operates in conjunction with the
Quiet/Open function. Refer to Radio Interface pin functions.
7
Configuration
Module Configuration
The operating parameters and functions of the CM1481 are programmed to the module (in its CONFIG mode) via
the Configuration Interface Connector from a PC running CML Configuration software.
The CM1481 is supplied, initially, configured to the DEFAULT settings as shown in the example menu below.
Over Air Re-Configuration will enable the changing of the following:
Tx Address
Transpond Mode
Rx Address
ANI Address
Transpond Address
ANI Mode
To make changes to any other parameters a base-conducted configuration operation must be carried out.
The following pages and diagrams describe the Configuration operation.
Configuration Interface Connector
Illustrated below is the termination information for the construction of the Configuration Interface Connector.
13-Way SIL
CM1481 Connector
25-Way “D”
PC Printer Port
Configuration
Function
J1 - 13
-
+ve Supply Input
J1 - 12
to
LPT1 - 18*
GND
J1 - 8
to
LPT1 - 13
Data Out
J1 - 4
to
LPT1 - 2
Data In
J1 - 3
to
LPT1 - 1
Clock
J1 - 1
to
LPT1 - 19*
Config
-
LPT1 - 20*
GND (0V Supply)
Table 3 Configuration Interface Connector - Terminations
* Pins LPT1 -18, -19 and -20 are connected to GND inside the PC.
8
Configuration ......
Configuration Instructions
The CM1481 is configured using a PC running simple CM1481 menu-driven software via the Configuration
Interface Connector between the PC Printer Port (LPT1) and the CM1481 Connector (J1).
Using the menu, configuration parameters are defined in the PC and then written to the module.
When configured the module will retain these parameters until re-configured by either: (a) Over-Air
Re-Configuration, or (b) complete PC repeat configuration. A power supply of the relevant value is introduced via
the Configuration Interface Connector for module power during configuration (see Table 3).
The previous page details the construction and connections of the Configuration Interface Connector and
shows an example screen of the DEFAULT software menu.
Preparation and Configuration
1. With no power applied connect the CM1481 (J1) to the PC Printer Port (LPT1) via the configuration
Interface Connector.
2. Start the computer.
- CM1481 Configuration software will run under MS DOS versions: 3.2, 3.3, 4.01, and 5.0 3. With the CM1481 Configuration program disk inserted in the floppy drive, type : <(Drive): CM1481.EXE>
4. The CM1481 Configuration Main Menu will be displayed.
Follow the initial instructions.
5. Provide power to the module via the Configuration Interface Connector.
6. With reference to the function keys at the bottom edge of the screen --<EXIT> Exits the Configuration program and returns the user to the DOS prompt.
<EDIT> Enters ‘Configuration-Edit’ mode to change parameter/function set-ups.
<UP, DOWN> Moves a highlighting cursor to the required parameter.
<LEFT, RIGHT> Decreases or increases the chosen parameter value.
<CHANGE ADDRESS> When the cursor is placed within an address field, the <CHANGE
ADDRESS> function may be activated; this will allow the address to be entered as one entity.
<EXIT to PREVIOUS SCREEN> Returns to the previous screen.
<LOAD> loads a previously saved set-up file.
<SAVE> saves the current set-up file.
<READ> reads the set-up information from the module.
<WRITE> writes the selected set-up file to the module. This will overwrite any resident information.
<VERIFY> A comparison of the screen setup and the written setup.
<REVISION> reads the current firmware (CM1481 on-board software status) from module.
7. When the <WRITE> command is completed powerdown the module.
With power removed from the radio, reconnect the Radio Interface.
8. To configure another CM1481 module, remove the power from the module.
Remove the current module from the Configuration Interface Connector.
Connect the new module and continue from Step 5 (above).
9. CONFIGURATION COMPLETE.
9
CM1481 - Configuration Men
u
Menu
The table below indicates the functions of the CM1481 and the options that may be achieved via software
configuration. Details in BOLD TYPE indicate DEFAULT settings.
CM1481 CONFIGURATION PROGRAM
Function
Default
Transmit Address:
Receive Address:
Transpond Address:
ANI Address:
Toneset:
Tone Length:
NOTONE Timer:
Lead-In Delay:
Lead-In Tone Length:
Lead-In Tone Digit:
Number of Called Alerts:
PTT Time-Out:
Pseudo Iterations:
Timed Mute Reset:
Extended Data Tone (Tx):
Call When Quiet:
Radio “Stunned”:
Operation:
Start-Up State:
ANI Mode:
Transpond Mode:
Tones per Address:
Lead-In Gap:
Over-Air Functions:
Extended Group Tone (Tx):
Open Mode:
LED Call Memory:
Beep Mute State:
PTT In:
ActivePTT Out:
ActiveBusy:
ActiveMute:
ActiveLED:
ActiveQuiet/Open:
ActiveCall:
Active-
0 1 2 3
6 7 8 9
2 1 0 1
6 5 4 3
ZVEI1
70ms
100ms
200ms
OFF
0
15
OFF
32
OFF
No
No
No
Single
Quiet
OFF
OFF
5
No
Disabled
No
Unmute
OFF
Unmute
LOW
LOW
LOW
HIGH
HIGH
LOW
LOW
Options
4
0
8
2
5 OR (6)
VALID ADDRESS TONES
CCIR EEA ZVEI1 ZVEI2 ZVEI3 PZVEI
30 to 150ms in 10ms steps
20 to 300ms in 20ms steps
OFF, 0 to 2550ms in 10ms steps
OFF, 0 to 2550ms in 10ms steps
123456789ABCDEF
0 to 15 in steps of 1
OFF, 10 to 248secs in 1sec steps
1 to 255 in steps of 1
OFF, 1 to 255secs in 1sec steps
Yes or No
Yes or No
Yes or No
Single or Dual -Button
Quiet or Open
OFF, Lead, Trail or Lead & Trail (both)
OFF, Address or Beep
5 or 6
Yes or No
Disabled or Enabled
Yes or No
Unmute or Transparent
On or OFF
Mute
HIGH or LOW
HIGH or LOW
HIGH or LOW
LOW or LOW
LOW or LOW
HIGH or LOW
HIGH or LOW
Table 4 Configuration Options
Further information on CM1481 functions is given in the Functional Descriptions section of this
manual.
CM1481 Configuration Software, Module firmware and documentation provided are supplied ‘as is’. Under this condition CML makes
no warranty, express or implied, of the saleability of this media or its fitness for a particular purpose. Under no circumstances whatsoever
will CML be liable for ANY damage, loss of profits, or any consequential loss arising from the use of this media, even if CML has been
advised of the possibility of such loss. CML does not assume any responsibility for the use of any of the circuitry described. No circuit
patent licences are implied and CML reserves the right at any time without notice to change the said circuitry.
10
Configuration ......
Error and Status Messages
Error and/or Status Messages as described below will appear on-screen, in the area above the Function Key
menu, during the operation of the Configuration Software.
Checking Module Communications:
A READ/WRITE/READ/WRITE action to confirm
communications between the PC and the Module.
Error in Module Communications:
Problems encountered when communication attempted with
module. Check for correct connections and power supply.
Writing Module Setup:
WRITING to the Module.
Error in Writing to File:
Cannot write due to insufficient disk space, Write Protect,
Read Only, etc. ......
Verifying Module Setup:
Comparing the WRITTEN setup with the screen version.
Setup not Verified:
A comparison of the screen setup and the module written
setup have produced a disparity. Use a <READ> command to
check the setup.
Verify OK:
The current screen setup has been WRITTEN then READ;
versions are the same.
Writing Complete And Verified:
Successful WRITE action.
Reading Module Setup:
READING the configured module setup to the screen.
Error in Opening File:
File name not recognized or located.
Error in Reading from File:
File open but cannot be READ from..
Reading Complete:
READ action successful.
Reading Firmware Information:
READING ‘version’ information to the screen.
Firmware Information Recovered:
Firmware information displayed is correct.
Incorrect Address Length:
Too few elements in the setup. Re-enter the correct address.
Invalid Address Characters:
Invalid characters used in setup. Re-enter the correct address.
Invalid Module Setup:
[WRITE current setup to module first]: The parameters
entered will not produce a valid Selcall setup. The screen will
revert to the previous setup; this must be written to the module
before continuing.
Error Messages will FLASH on the screen and are cancelled by using the relevant Function Key.
Status Messages indicate operational progress and remain steady on the screen during the action that they refer
to.
11
Functional Descriptions
Receive Call
Operation
Individual Selcall Receive Sequence
Unit’s Rx Selcall Address is decoded
i
If Transpond configured the unit transponds
ii Audio Open; "Open" Alert is output
iii "Call Received" Alert is output; LED output is pulsed
Alert cancelled by ’blip’ of PTT, Call
or Quiet/Open buttons, or Time-Out
i
Alert beeps stop
Conversation takes place; Conversation complete
Radio is muted by: push-button/Timed Mute Reset
/Remote Reset
i Unit "Closed" Alert is output.
Radio is Closed.
GROUP Selcall Receive Sequence
i
ii
A GROUP-call with the unit’s Rx Selcall
Address is decoded
No transpond can take place for a GROUP-Call
"GROUP-Call" Alert is output; this alert is self cancelling
The calling party transmits the message/s
The CM1481 can only reply to an originator whose Tx Address is
configured, and not to the other GROUP members - Conversation complete.
Radio is Closed by: push-button/Timed Mute Reset
/Remote Reset
i Unit "Closed" Alert is output.
Radio is Closed.
Fig.5 Rx Call Operation
Transmit Call
Operation
Normall Selcall Transmit Sequence
i Unit "Open" Alert is output.
ii Radio squelch circuitry released to normal operation
Unmute the radio by push-button operation (see Single/DualButton operation)
- or employ ’Muted Call’ initiation Method
Monitor the channel.
Transmit the (Tx Address) Selcall by push-button
operation
Note that if the BUSY input is active, a call
cannot be transmitted (PTT Lockout)
A
B
i "Call Transmitted" Alert is output
ii Tx ON is active; the Selcall is output at TONE OUT
If the system is ’No Transpond’, when the called station’s reply is received the converstaion may continue.
If the system is ’Transpond’, await the transpond action then conversation may continue.
i
Start Conversation
PTT Timer started
Conversation complete
Radio is Closed by: push-button/Timed Mute Reset
/Remote Reset
i Unit "Closed" Alert is output.
Radio is Closed.
Fig.6 Tx Call Operation
LED Drive
A polarity programmable LED drive output is available if a visual indication of a received
Selcall is required. It is recommended that, under LED conditions, this output is configured
as an “active high” and an external LED is connected directly to GND (0V).
With due regard to the specified current limits, this output may be used to activate mobile
horn-honk/indicator driver circuits.
LED Call
Memory
If the ‘Selcall Received Alert’ has been activated but not cancelled, the module can be
configured so as to leave the LED illuminated as a Call Memory.
The use of any push-button function will cancel this LED action.
Configured as LED Call Memory:
12
Functional Descriptions ......
Audio Alerts
The CM1481 will provide 'alert' output signals to be used in an audio system to indicate
and highlight certain operations; these are described below.
The alert output signal takes the form of a square-wave at the frequencies and durations
described.
It is recommended that the Alert output is introduced to the receiver audio amplifier stages
after the squelch gate and with due regard to any audio powersave functions.
To facilitate either loudspeaker or amplifier operation, a removable LINK is provided on the
CM1481 PCB. To drive a loudspeaker, leave the LINK in place. To interface with an
external amplifier, remove the LINK (see PCB Layout, Figure 4).
Cause of Alert
Alert Description
Frequencies
Entering ‘Quiet’ condition Short duration low-pitch beep
1 x 200ms at 250Hz
Entering ‘Open’ condition Short duration high-pitch beep
1 x 200ms at 1kHz
Selcall Received
A train of rapid mid-pitch beeps
(‘n’ configured as “Called Alerts”)
cancelled by a PTT, CALL or QUIET/OPEN action ‘n’ x 200ms at 1.25kHz
[+ activation of LED output.] See LED Call Memory
GROUP Call received
3 short duration mid-pitch beeps
3 x 200ms at 750Hz
Selcal transmitted
Short duration mid-pitch beep
1 x 100ms at 500Hz
Tx Time-out warning
Short duration high-pitch beep
1 x 100ms at 1.5kHz
PTT action disabled
Continuous low-pitch tone
347Hz
CALL action disabled
Continuous low-pitch tone
347Hz
Table 5 Audio Alert Descriptions
PTT Lockout
Automatic
REPEATTone
An internal operation carried out by the CM1481 that will prevent the Tx On line being
placed in an active condition irrespective of the state of the PTT In input.
Conditions that cause a PTT Lockout are:
• An active ‘BUSY’ input.
• The CM1481 in the ‘Quiet’ (muted) condition.
• PTT Timeout expired and not reset.
If in any tone sequence (address or data) one tone character is identical to the preceding
one, to prevent confusion at the decoder a REPEAT-tone (‘E’) must be transmitted in its
place.
At configuration the CM1481 addresses are entered using the code characters ‘0’ thro ‘A’
and identical characters entered as required.
The PC software then processes the address inserting REPEAT-tones as necessary
before writing the information to the module. The REPEAT-tone must not be used as the
first character of a sequence; Address/Data tones received by the CM1481 must conform
to the REPEAT-tone rule for complete decode accuracy.
Example:
Required Sequence
1 2 3 3 5
Timed Mute
Reset
Transmitted Sequence
1 2 3 E 5
When configured this function will automatically close (re-mute) the CM1481, if in the Open
mode, after the configured time-period of inactivity.
Configured as Timed Mute Reset:
13
Functional Descriptions ......
Single or
Dual Button
Operation
The CM1481 can be configured to one of two modes of user control.
Dual Button mode. The ‘Quiet/Open’ switch toggles the ‘Quiet/Open’ (mute) function; the
‘Tx Call’ switch initiates a Selcall ‘Tx Call’.
If it is required to operate in a unit with no local means of ‘Quiet/Open’ operation, this
dual-button mode should be configured but the ‘Quiet/Open’ input not connected
internally.
Single Button mode. A single switch (push-button) connected to either ‘Quiet/Open’ or
‘Tx Call’ inputs controls both Mute and Selcall operations.
A “press” of less than 1-second will toggle the ‘Quiet/Open’ condition; a “press” of more
than 1-second will initiate a Selcall.
Both inputs can be configured to active “High” or “Low” polarities; with reference to the
CM1481, both inputs are connected, on-board, to the positive supply rail (VDD) via 47kΩ
pullup resistors.
For an active “Low” input, the switches should be connected directly to 0V (GND).
For an active “High” requirement, the on-board pullup resistors must be considered.
Configured as Operation:
+ve
supply rail
Quiet/Open
Tx Call
pullup resistors
Fig.7 Operating Button Connections
Automatic
Number
Identification
(ANI)
Each unit is assigned a unique ANI code which enables identification of a transmission. In
the CM1481 this code is programmable, both by initial configuration and by over-air
re-configuration, as the ANI address.
When enabled the ANI code is transmitted at the beginning (leading) and/or the end
(trailing) of a transmission. In the CM1481 the ANI operation is selectable by configuration
to either OFF, Lead, Trail, or Lead and Trail.
If the PTT Time-Out function is activated, a trailing ANI (if configured) is transmitted
before shut-down.
Configured as ANI Mode: and ANI Address:
Mic key reset; signifying
end of conversation
PTT In
(active "low")
Tx remains keyed
for ANI period
Tx ON
(active "low")
Tone Out
Leading
ANI
Trailing
ANI
Fig.8 ANI Functional Diagram
14
Functional Descriptions ......
Input/Output
Polarities
The following input and output activation polarities may be set at configuration.
Function
Notes
On-Board State
Connected To
Pullup to VDD
- the microphone end of the radio PTT line
Pullup to VDD
- Rx carrier detect circuitry
PTT In
Input
Tx On
Output
Busy
Input
Mute Ctrl
Output
- to operate the radio squelch gate
LED
Output
- to drive an LED to provide a visual alert
- the PTT line to the Tx circuitry
Quiet/Open
Input
Pullup to VDD
- to control the radio mute state
Tx Call
Input
Pullup to VDD
- Selcall initiation
Table 6 Input/Output Programmable Polarities
Tx Timeout
and
Warning
To prevent nuisance and to regulate transmissions to a reasonable period, the PTT
Timeout function will disable all PTT Tx functions after a pre-determined (configured) time
period.
When the PTT is activated the PTT Timer will run for the configured interval giving an
Audible Warning 6-seconds before the timeout. If the PTT is still active 6-seconds after
the warning the transmission will be aborted at that time and all PTT functions completely
disabled for a short period (6-seconds) to enable other users the opportunity to enter the
channel.
Although not recommended, if the the PTT is released and re-keyed frequently before the
PTT Timeout Warning, the PTT Timer will be reset and the Tx Timeout will not be
activated
Under Tx Timeout conditions, the PTT must be released and will not be re-enabled for a
predetermined period. The PTT Timeout period can be configured to OFF.
Configured as PTT Time-Out:
NOTONE Timer
A configurable function incorporated to indicate the end of a tone or tone sequence to the
on-board µController. For optimum CM1481 performance it is recommended that this
function be set to approximately 1.5 times the selected Tone Length.
Configured as NOTONE Timer:
Recommended NOTONES
Transponding
Toneset
Tone Length
NOTONE Period
EEA
40ms
60ms
CCIR
100ms
160ms
ZVEI
70ms
100ms
In reply to a Selcall the CM1481 can be configured to respond by transmitting either its
Transpond Address (Tp) or a BEEP (tone F). This function can be re-configured over-air.
Configured as Transpond Mode: and Transpond Address:
15
Functional Descriptions
Lead-In
Delay
A configurable delay period between the operation of the PTT and the Selcall Tone output
from the module. This function is available to allow sufficient time for the transmitter to
stabilize before modulation.
Configured as Lead-In Delay:
Lead-In Delay
PTT Out
(active "low")
Lead-In
Delay
Tone Out
Selcall Tones
Lead-In Tone with No Gap
Tone Out
Lead-In
Tone
Selcall
Tones
Lead-In Tone with Gap
-- the gap is 1 tone-length
Tone Out
Lead-In
Tone
Selcall
Tones
Fig.9 Lead-In Tone and Delay
Lead-In Tone
To operate on and gain access to, repeater systems the Selcall address output of the
module can be preceded by an extended tone. At configuration the tone operation, frequency and length can be set; if required a single Selcall tone-period gap between the
lead-In tone and the Selcall address may be set.
Configured as Lead-In Tone Length:, Lead-In Tone Digit: and Lead-In Gap:
Quiet/Open
Modes
The CM1481 has two audio operational modes - ‘Quiet and Open’
Open’.
Quiet/Open operations are initiated by:
(i) Pressing the Quiet/Open button (Dual Button operation) or a short press of the
Operate button (Single Button operation).
Quiet operations are initiated by:
(i) A Timed Mute Reset operation.
(ii) A Remote Reset command received.
Quiet
The radio Rx audio is muted.
PTT (Tx) action is disabled.
Selcalling can either be disabled or enabled via initial configuration. There are no operational
alerts except for PTT and Call Action Disabled or Selcall Transmitted (if configured).
Open
Open modes can be configured to either Unmuted or Transparent states.
If called in an “Open” mode received Selcall tones will be output at the loudspeaker.
Configured as Open Mode:
Unmuted:
The radio is unmuted (MUTE CTRL inactive) and the loudspeaker (hash) is enabled. All
functions are enabled and operate as configured.
Transparent:
The radio audio circuits act as if squelched; Audio output is dependant upon the presence
of an RF carrier (BUSY input). MUTE CTRL is only inactive if the BUSY input is active.
16
Functional Descriptions
‘Muted’ Call
Initiation
It is possible for the CM1481 to be embodied within a radio that has no local means of
Quiet/Open control; the CM1481 will be configured to Dual button operation but the Quiet/
Open input not used. Such a system will require the base station to operate its mute
system and open the squelch or re-mute with a Remote Reset command.
In a radio that has no local means of opening its mute function, the operator must initiate a
Selcall to the base; PTT Lockout will prevent any illegal voice transmission.
The base must be so configured as to contact the CM1481 fitted radio and lift the mute
function (and therefore allow normal operation) by replying with the unit's Receive Address.
Reception of its receive address Selcall will cause an alert beep sequence at the CM1481;
operation of the PTT will halt the alert and unmute the radio; normal operation may take
place.
Upon completion of the conversation the unit's operation will be reset (muted) by the base
with a Remote Reset command.
Configured as Call When Quiet:
Power-Up
'Quiet'/'Open'
The CM1481 can be configured to assume one of two mutes conditions upon power-up.
Quiet -- The audio output is muted; a Quiet/Open operation is required to monitor
channel activity.
Open -- The audio output is active; the channel can be monitored to ascertain activity
and correct operation.
Configured as Start-Up State:
Over-Air
Functions
(a) Remote Reset
(b) ‘Re-Configuration’
(c) ‘Stun’
(d) ‘Release’
The above operations may be carried out from a suitably configured remote station (the
controlling base) to:
(a) Mute a Radio:
Using a “C” or “D” tone appended to the units Rx Selcall address. See Figure 13.
(b) ‘Re-Configure’ the following parameters:
Tx Address
ANI Address
Transpond Address
Rx Address
ANI Mode
Transpond Mode
(c) ‘Stun’ a Radio:
To completely disable a CM1481 fitted radio unit.
Rx audio is permanently muted; PTT line is disabled; Selcall transmission is inhibited.
(d) ‘Release’ a Radio:
To release the CM1481 fitted radio from the ‘Stun’ mode and allow normal operation.
Over-Air function operation is enabled and disabled at Configuration as Over-Air Function:
17
Functional Descriptions ......
Security
Checks
To prevent unauthorised or ‘accidental’ over-air operations, items (b), (c) and (d), described
on the previous page are carried out using a secure authentication protocol based upon the
synchronization of two pseudo-random number generators, one in the base, one in the
CM1481 unit. Figure 10 shows an operational security transaction.
BASE transmits
Over-Air Request
BASE uses SEED
to generate KEY
1
BASE transmits
SEED for Security Check
2
Generates KEY
Security Check is allowed 15secs
3
Transmits KEY
4
BASE
KEY comparison
Correct comparison
= Action Complete
Transmits Comfirmation
CM1481
Fig.10 An Over-Air Security Transaction
Over-Air
Functions
On reception of an over-air request [1] the CM1481 will produce, and transmit, a random
SEED (random number) [2] which will set the start-count position for both pseudo-random
generators; under the control of the configured “Iterations” parameter both generators will
produce the KEY.
Correct KEY comparison will allow the over-air operation to be completed and confirmed
[3].
Each over-air operation requires its Security Check to be completed within a preset time
period of 15 seconds.
Failure to complete the transaction in the pre-determined time or an incorrect KEY
comparison will result in the cancellation and failure of the relevant operation.
Due to the covert manner of this operation the CM1481 will not produce an “OPEN” or
“Selcall Received” alert during these transactions.
Neither ANI or Transpond functions are available during Over-Air operations.
18
Functional Descriptions ......
Example
Over-Air
Transactions
STEP 1
Figure 11 (below) shows, in diagrammatic form, the sequence of tones for an Over-Air
Re-Configuration of the Tx Address between the controlling base station and the CM1481.
Figure 13 shows the complete range of tone sequences to be used with the CM1481. For
Over-Air transactions follow the steps illustrated in Figure 11 substituting the required
action in STEP 1 with the required request and confirmation from Figure 13. Note the use
of the Data Prefix tone “B” in the data field; all operations must conform to the HSC
Operational Rules which are described on the following pages.
Over-Air Re-Configuration Request (Tx Address)
DA
Pre TA
fix
Rx Address Tones
4
B
B
Security Reply (KEY)
-
2
from base
B
Configuration Confirm
-
Data Tone 3 Tone 4 Tone 5
Prefix
SEED Tones
s1, s2, s3
s1
s3
s2
KEY Tones
k1, k2, k3
k1
k3
k2
Rx Address Tones
STEP 4
B
from CM1481
Old Tx Address Tones
STEP 3
New Tx Address Tones
+ Data Prefix
Tone 1 Tone 2
-
Security Check (SEED)
from base
0
Tone 1 Tone 2 Tone 3 Tone 4 Tone 5
STEP 2
-
PA
FU
RA
N
TOCTIO TO MET
NE N
NE ER
3
from CM1481
New Tx Address Tones
B
8
Fig.11 Example Over-Air Re-Configuration Tone Transaction
PseudoRandom
Number
Information
The figure below shows the pseudo-random number generation in diagrammatic form.
The base unit controller's software and circuitry will require to emulate this function.
The SEED is a random 8-bit number produced by the CM1481. The SEED is loaded into
the register and shifted right by the amount of steps configured as: Pseudo Iterations.
Note the Exclusive-OR functions.
The result is the KEY.
s1/k1
s2/k2
Parallel "SEED"
7 MSB
6
5
s3/k3
/ Parallel "KEY"
4
3
2
1
Ex-OR
Register Shifted Right 1 Step per Configured Iteration-Step
Fig.12 An 8-Stage Pseudo-Random Counter Employing Exclusive-OR Feedback
19
0 LSB
Feedback
Functional Descriptions ......
Over-Air Tone Information
-
Over-Air Re-Configuration Request (Rx Address)
from base
PA
FU
RA
N
DA
T ME
TOCTIO
Pre TA
NE N ONE TER
fix
Rx Address Tones
B
4
New Rx Address Tones
+ Data Prefix
1
B
Tone 1 Tone 2 Tone 3 Tone 4 Tone 5
Tone 1 Tone 2
-
Over-Air Re-Configuration Request (Transpond [Tp] Address)
from base
New Tp Address Tones
+ Data Prefix
Rx Address Tones
B
4
2
-
Over-Air Re-Configuration Request (ANI Address)
B
from base
New ANI Address Tones
+ Data Prefix
Rx Address Tones
B
4
3
B
Over-Air Re-Configuration Request (Transpond [Tp] Mode)
-
from base
m
m =
=
=
=
0
1
2
3
=
=
=
=
OFF
Tp Address
Reserved
BEEP
m =
=
=
=
0
1
2
3
=
=
=
=
OFF
Leading
Trailing
Leading & Trailing
Rx Address Tones
B
4
4
-
Over-Air Re-Configuration Request (ANI Mode)
from base
Rx Address Tones
B
Over-Air STUN Request
-
4
5
from base
B
-
1
from CM1481
Tx Address Tones
B
Over-Air RELEASE Request
-
6
from base
Rx Address Tones
B
m
FUNCTION Tones
Rx Address Tones
Over-Air STUN Confirm
Data Tone 3 Tone 4 Tone 5
Prefix
0
Reserved
1
STUN Request
2
Security Check
3
Security Reply
4
CONFIGURE Request
5
RELEASE Request
6
STUN Confirm
7
RELEASE Confirm
8
CONFIGURE Confirm
9, A, B, C, D, F,
5
Reserved
PARAMETER Tones
Over-Air RELEASE Confirm
-
from CM1481
Tx Address Tones
B
Remote Reset
-
7
from base
Rx Address Tones
C or
D
Fig.13 Tone Sequence Information
20
0
Tx Address
1
Rx Address
2
Transpond (Tp) Address
3
ANI Address
4
Transpond (Tp) Mode
5
ANI Mode
6, 7, 8, 9
Reserved
A, B, C, D, F
Reserved
Functional Descriptions ......
HSC
Hexadecimal
Sequential
Code
An in-band audio signalling system used for the communication of Address and Data
information using sequential tone signalling.
Sequential tone signalling has been adopted to national and international standard tonesets.
The CM1481 will operate to any one of the following tonesets in both frequency and tonelength. The required toneset is selected at initial configuration from the selection shown below.
Tone No
(Hex)
EEA
CCIR
ZVEI 1
PZVEI
ZVEI 2
ZVEI 3
\DZVEI
0
1981
1981
2400
2400
2400
2200
1
1124
1124
1060
1060
1060
970
2
1197
1197
1160
1160
1160
1060
3
1275
1275
1270
1270
1270
1160
4
1358
1358
1400
1400
1400
1270
5
1446
1446
1530
1530
1530
1400
6
1540
1540
1670
1670
1670
1530
7
1640
1640
1830
1830
1830
1670
8
1747
1747
2000
2000
2000
1830
9
1860
1860
2200
2200
2200
2000
A
1055
2400
2800
970
885
825
B
930
930
810
810
810
740
C
2247
2247
970
2800
740
2600
D
991
991
885
885
680
885
E
2110
2110
2600
2600
970
2400
F
2400
1055
680
680
2600
680
Table 7 Tone Frequencies (in Hz)
Operational
Rules
To ensure all-system compatibility, the CM1481 has been designed to operate to the
following rules.
Base and other units working with the CM1481 must conform to these rules.
1 All calls, commands and interrogations to, and calls from, the CM1481 are prefixed
with a 5 (or 6)-tone HSC format Selcall Address.
2 Full international group-calling is possible to more than one user group via GROUP
and REPEAT tones.
3 A DATA FUNCTION tone “B” is appended after the Selcall address. No more than 4
adjacent DATA tones are allowed; if more than 4 are required, a DATA FUNCTION
tone should be inserted after every fourth DATA tone.
4 The DATA FUNCTION tone may be lengthened to twice the chosen toneset length
under the control of the Extended Data Tone command at initial configuration.
5 If in any tone sequence (address or data) one tone character is identical to the
preceding one, to prevent confusion at the decoder a REPEAT-tone [‘E’] must be
transmitted in its place.
21
Functional Descriptions ......
Tone
Allocations
Character
0 thro' 9
Function
Decimal digits in the address or data fields.
A
GROUP character in the address field or ”AHEX” in the data field.
B
Data prefix tone or “BHEX” in the data field.
C
REMOTE RESET character address code suffix or “CHEX” in the data field
D
REMOTE RESET character address code suffix or “DHEX” in the data field
E
REPEAT character
F
“FHEX” in the data field
Table 8 Tone Allocations
International
GROUP
CALL
The international standard for calling a specific group of units by inserting the GROUPTone (‘A’) into a Selcall.
The GROUP-Tone (‘A’) represents all tone digits from 0 to 9. Any character in the Selcall
address can be replaced by a GROUP-Tone (‘A’); a second consecutive GROUP-Tone
should be replaced by a REPEAT-Tone. The flexibility of placing GROUP-Tones within a
Selcall Address allows more user-groups to be set-up.
Example:
Address Sequence
1
1
1
1
NonInternational
GROUP
CALL
234A
2A45
A34A
2AEA
Addressed Units
12340
12045
10340
12000
to
to
to
to
12349
12945
19349
12999
To provide compatibility with Selcall systems where the only characters permitted to
follow a GROUP-Tone (‘A’) in a sequence are other GROUP- or REPEAT-Tones.
Under this protocol, the first GROUP-Tone is extended to 3 times the normal system
length.
To transmit to such a system as opposed to an International system, the Extended
GROUP-Tone (Tx) option must be selected at initial configuration. This method restricts
the number of Groups available.
Example:
Address Sequence
1234A
123AE
12AEA
1AEAE
AEAEA
Addressed Units
12340
12300
12000
10000
00000
to
to
to
to
to
12349
12399
12999
19999
99999
The CM1481 is able to transmit and respond to both International and Non-International
GROUP-Calls.
The Transpond facility (Tp) is not available for GROUP-Calls.
The GROUP-Call character can be configured into any address set-up.
22
Specification
Absolute Maximum Ratings
Exceeding the maximum rating can result in module damage. Operation of the module outside the operating limits
is not implied.
Supply voltage
6.0V to 26.0V
Operating temperature range: CM1481
CM1481
Storage temperature range:
0°C to +70°C
-20°C to +85°C
Operating Limits
All module characteristics are measured under the following conditions unless otherwise specified:
VIN = 6.0V to 12.0V, TOP = 0°C to +70°C.
Characteristics
Supply Voltage (VIN)
Operating Current (Tx/Rx)
Standby Current
LED Drive Current
Current Limits (PTT and Mute O/Ps)
Input Sensitivity
Tone Out Level
Tone Out Accuracy
Alert-Tone Output Level
Tone Decode Bandwidths
CCIR
EEA
ZVEI
Signal -to-Noise Performance
Logic “1” In
Logic “0” In
LED Logic “1” Out
LED Logic “0” Out
Audio Switch Signal
Alert Output Impedance
See Note
7
1
2
Typ.
Max.
Unit
6.0
31.0
-
9.5
2.5
308
250
26.0
15.0
50.0
±0.1
-
V
mA
mA
mA
mA
mVrms
mVrms
%
mV p - p
13.8
1.0
0.4
5.0
1.0
-
% fc (Hz)
% fc (Hz)
% fc (Hz)
%
V
V
V
V
Vp-p
Ω
kΩ
MΩ
kΩ
kHz
MHz
3.5
0
4.2
-
3
6
6
4
5
Signal Input Impedance
Signal Output Impedance
Configuration Clock Rate
On-Board Xtal Frequency
Notes
1
2.
3.
4.
5.
6.
7.
Min.
±2.30
±2.30
±3.80
100
140
100
20.0
10.0
4.0
Under pure-tone conditions.
The ‘Alert’ square-wave driving an 8Ω load with on-board LINK in position (see Figure 4).
At -4.0dBs S/N (using a 100ms CCIR signal at 248 mVrms).
With on-board LINK in position.
With on-board LINK removed.
PTT, CALL, QUIET/OPEN, BUSY, CONFIG. Inputs.
The standy condition is when the CM1481 is in the Quiet mode.
23
Or
dering Inf
ormation
Ordering
Information
CM1481
Non-Predictive Selcall Module
[Module + Radio Interface]
CK1481
Configuration Kit
[Configuration Interface Connector
+ Software {51/4 & 31/2" disks} ]
CML does not assume any responsibility for the use of any circuitry described. No circuit patent licences are implied
and CML reserves the right at any time without notice to change the said circuitry.
CONSUMER MICR
OCIRCUITS LIMITED
MICROCIRCUITS
1 WHEATON ROAD
WITHAM - ESSEX CM8 3TD - ENGLAND
© 1992 Consumer Microcircuits Limited
Telephone: (0376) 513833
Telex: 99382 CMICRO G
Telefax: (0376) 518247