Data Sheet AS2574B 20 NUMBER ONE TOUCH DIALLER WITH SERIAL BUS FOR DISPLAY DRIVER Austria Mikro Systeme International Key Features General Description ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ The AS2574B is an integrated CMOS device for feature telephones. It is a very versatile LD/MF dialler with serial interface to a display driver. The device is designed to be used in a wide variety of applications together with the companion display driver, AS2590. ❑ ❑ ❑ ❑ Low operating voltage (2.5V to 5.5V) Low current consumption (typ. 200 µA in LD mode) Oscillator using ceramic resonator (681 kHz) MF level independent of supply voltage Direct ´wake-up´ from keyboard Automatic Call Progress by direct memory key Data protection with 8 digit FIFO Sliding cursor protocol with comparison Diode options for different PTT requirements Automatic pause generation after access code Temporary MF select via keyboard 36 digit LNR (Last Number Redial) 20 memories addressable with direct keys and the 2nd key or indirect with a MEM key Notepad Serial interface to display driver AS2590 Consistent, simple and useable procedures Input for dial tone recognizer The on chip RAM can contain up to 20 memories (each with maximum 18 digits), a 36 digit Last Number Redial (LNR) and an 18 digit notepad. Access to the 20 memories is either with direct keys, abbreviated dial code or a combination of both. The AS2574B provides a unique feature, Automatic Call Progress (ACP), on all memory keys, i.e. the circuit automatically seizes the line and waits for the dial tone and dials the number just by pressing any of the memory keys (including LNR). The circuit features 2 different access code procedures to allow easy use under a PABX. A dial tone input enables the use of a dial tone recognizer. Application Package High feature telephone sets. Available in 28 pin DIP and PLCC. La The wake-up feature allows the user to go off-hook by pressing a direct memory key or a loudspeaker key, so-called onhook dialling or call progress monitoring, and thereby seize the line. Rev. 1 Lb E Flash DP 1 2 3 4 5 6 7 8 9 * 0 # LS LNR M9 ENTER M 1 M5 R1 R M2 M6 R2 2ND M3 M7 R3 MUTE M 4 M8 R4 MEM M10 R5 C6 C5 C4 C3 C2 C1 MODE ACP M/B MS DIALLER/CONTROLLER ER Ground Loop SPEECH VDD LOUDHEARING HS HANDSFREE MASK TONE RINGER TONE 681kHz OSC1 OSC2 TB AS2574BCD Vss MT SCL SDA MR LS VDD MS SDA SCL V23 V13 AS2590 Direct wake-up is an AMS patented solution providing line seizing with a telephone, that is entirely powered from the telephone line, by pressing a key in a key matrix connected to a dialler/controller that is constantly connected to the line by means of a line voltage limiter and yet maintaining a high dc isolation resistance in idle state (on-hook). 32.768kHz X1 X2 BIAS VLCD Vss DISPLAY 1 Jan. 1995 Data Sheet AS2574B Pin Description Pin # Pin Node Description 1 2 OSC2 OSC1 Oscillator pins for ceramic resonator (681 kHz) 3 4 SCL SDA 5 - 10 C1 - 6 Keyboard columns 11 - 15 R1 - 5 Keyboard rows 16 LS 17 MASK 18 CD The SCL output is used to clock all data into the display driver The SDA output is used to transfer data into the display driver Output for controlling loudhearing and handsfree facilities, active high (see hook state diagramme) Mask output, active high during pulsing (make and break period, see timing diagrammes). Chip disable input, active low. When CD is low, the circiut is disabled. If this pin is pulled to VSS during Off-hook (indicating a disconnect) for more than 2 sec., the circuit is reset*. If the pin is pulled to VSS for less than 2 sec., the line break is ignored. * If in ACP or monitor state, reset also means return to idle state. 19 MR Mute output, active high during signalling (see timing diagrammes). 20 MT Transmit mute output, active high when MR is high and when the Mute key has been activated (see timing diagrammes). 21 ER Earth recall input/output, active high during ER but when forced to VDD, the flash is enabled. 22 DT Dial tone input. This input is scanned when invoking ACP or a pause is read in a digit string: DT pin Function Open Pause duration 4.1 sec Low If a high is not detected within 8 sec., the circuit is reset * High If the pin is high for > 1.15 sec., the pause is terminated and the dialling continued. Noise immunity > 8 ms * Reset means that dialling is stopped and the circuit returns to standby. If the circuit was in ACP state, the reset will also return the circuit to idle state. 23 DP Hook switch control, dial pulse and flash output; low during Idle and break periods and high during off-hook (see timing diagrammes). Continues… Rev. 1 2 Jan. 1995 Data Sheet AS2574B Pin Description Continued Pin # Pin Node 24 HS Hook switch input; active high with internal pull-down resistor. Debounce 25 ms. 25 Vss Negative terminal of power supply. 26 TB Tone burst output: 27 Description TONE LS high 80 ms burst, 8 sec pause MT high 80 ms burst, 2 sec pause MT+LS high 80 ms burst, 2 sec pause Only in speech mode MF tone output. An on chip reference voltage provides tone levels independent of the supply voltage. A dc path from TONE output is needed to accommodate an external voltage divider for setting the appropriate tone level. Frequencies: Frequency (Hz) Key Matrix (Hz) 697 770 852 941 1209 1336 1477 1633 28 Vdd row 1 row 2 row 3 row 4 col. 1 col. 2 col. 3 see p. 7 Error (%) ≤ ± 0.7% Positive terminal of power supply Keyboard Layout ROWS COLUMN 1 2 3 4 5 6 1 1 2 3 ENTER M1 M5 2 4 5 6 RECALL M2 M6 3 7 8 9 2ND M3 M7 4 * 0 # MUTE M4 M8 5 LS LNR M9 MEM M10 The keyboard is arranged in a 5 x 6 contact matrix with single pole single throw contacts (SPST). Keyboard resistance: Ron < 5 kΩ; Roff > 5 MΩ. Rev. 1 3 In off-hook state all keys are enabled (CD = high) Enabled only when off-hook Enabled also when ACP is active (diode 5 inserted) Enabled when CD = high Jan. 1995 Data Sheet AS2574B following procedures revert it to default LD mode: Power On Reset The on chip analogue power on reset circuit monitors the supply voltage (VDD). As long as VDD remains below the internal reference voltage, VREF (typically 1.2V), the oscillator is inhibited. When VDD rises above VREF, a reset signal is generated to assure correct start-up, and the oscillator is enabled. - pressing R key (all subsequently entered digits are buffered in FIFO), - by next On-hook. Last Number Redial The correct start-up/reset condition of the circuit is guaranteed regardless of the absolute and chronological rise time of VDD, CD and HS inputs. LNR is a facility that allows resignalling of the last manually dialled number without keying in all the digits again. The LNR is repeatable. Line Supervision A manually entered number is automatically stored in the LNR RAM. The capacity of the RAM is 36 digits. If a number greater than 36 digits is entered, the LNR facility will be inhibited (until new entries < 37 digits) and further entries will be buffered in FIFO. If more than 18 digits are entered, the display will show the digit 19 and onwards. In off-hook condition the device performs supervision of the line current disconnects in the following manner: Line disconnects (CD low) of less than 2 sec. are ignored and the device continues operation. Line disconnects of more than 2 sec. cause stop of dialling and the circuit is switched to standby mode if HS is high, otherwise the circuit will return to idle mode. Postdialled digits, i.e. digits manually entered after LNR has been invoked, are not stored in RAM but buffered in FIFO. Valid Keys The current contents of the LNR RAM are overwritten by new entries. A valid key is detected from the keyboard by connecting the appropriate row to the column. This can be done using an n x m keyboard matrix with single contacts. Positive and negative edges of each contact are debounced. The debounce time is 15 ms. Memory Dial An on chip RAM enables the dialler to store up to 20 numbers, each containing a maximum 18 digits/data. In idle state (on-hook) only the LS key is always valid independent of the CD pin. When diode 5 is connected, also the LNR, MEM, and M1 - 9 keys are valid entries invoking ACP (automatic call progress). The first 10 memories are accessible with 10 Direct dial keys (M1 to M10) and another 10 memories (11 - 20) are accessible by pressing the 2nd key before one of the Direct dial keys or by pressing the MEM key and a digit 0 - 9 (abbreviated dialling). Mute Key Basic store procedure: Depressing the Mute key activates and deactivates (toggle switch) the MT output, when internal mute is inactive, i.e. when no data is being read from the RAM or FIFO. 1 Press Enter key 2 Key in digits, including access code, pauses and recall as appropriate (number is stored in LNR RAM) A change of the hook state will release the mute. 3 Select location by keeping Enter key depressed while entering the desired location (M1…M10, 2nd M1…M10, or MEM 0…9) Mode Selection The default mode (LD or MF) can be selected by the diode option mode (diode 6). 4 Release Enter key to finish When default LD mode is selected, a temporary change to MF mode can be invoked by pressing the * key. 5 Continue with 1, 2, 3 and 4 for storing further numbers. When the circuit is in temporary MF mode, each of the Only the first 18 digits/data will be stored when copying more than 18 digits/data in a memory. Rev. 1 4 Jan. 1995 Data Sheet AS2574B Recall Function Pause Generation A recall activation will invoke a flash (timed loop break) or an earth recall (ER) depending on the ER pin. When the ER pin is forced to VDD, a flash is executed; and when ER is open (> 50 kΩ}, an earth recall is executed. Pause introduces a delay in signalling digits strings to accommodate second and subsequent dial tones. Automatic pauses are generated: If R is the first entry in a digit string, it will be stored in LNR RAM. - during dialling out from memories when the first digit(s) in the digit string equal the stored access code(s) (pause depends on DT input). If the R key is depressed after a digit string has been dialled out, the recall will not be stored, and subsequently entered digits will be buffered in the FIFO. - when going Off-hook by pressing LNR, MEM, or M1 9 (ACP). A recall will automatically generate a pause when a recall is read from a memory and therecall has been stored as an access code. Any pause can be terminated (shortened) prior to time out by pressing the LNR key or a high level on the DT input. A manual invoked earth recall will pull ER high for minimum 500 ms, but the ER pin is maintained high as long as the key is depressed. During ACP a pause time out, i.e. DT kept low for > 8 sec., will return the device to idle state. Pauses are storable as digits within a string of any of the memories by pressing 2nd # during programming. Multiple pause entries can be stored up to the maximum length of the digit string (18 digits/data). A pause is not accepted in location 1 of a digit string. During auto dial an earth recall is executed with a duration of 500 ms. Access Codes Different access codes (totally up to 18 digit/data including spaces) can be stored in one string. Spaces between the different access codes are entered by pressing the 2nd # during programming. Each access code can contain up to 4 digits. If more pauses have been stored in succession, they can all be terminated by one depression of the LNR key or a high level on the DT pin for ≥ 1.15 sec. Sliding Cursor Procedure If one or more access codes are stored, the first entered digit(s) in a digit string read from the RAM will be compared with the access code(s) and if equal, a pause is generated. To accommodate redialling (LNR) behind a PABX without using automatic pause generation (storing access codes), a sliding cursor protocol is implemented. If new entries match the previous LNR RAM contents, pressing the LNR key will dial out the remaining digits. Example on programming access codes: If there is an error in matching, the LNR will be inhibited until next On-hook, and the LNR RAM will contain the new number. ENTER, 9 , 2nd #, 50 Keep ENTER depressed while pressing 0 Release both The first access code in this example is 9 and the second 50. Rev. 1 5 Jan. 1995 Data Sheet AS2574B low. SDA state changes during SCL high are reserved for indicating start and stop conditions (see figure 1). Serial Interface The AS2574B supports a serial bus. The protocol defines device that sends data onto the bus as a transmitter, and the receiving device as the receiver. The AS2574B is controlling the transfer and hence the master. The display driver, AS2590, being controlled is the slave. Start Condition All commands are preceded by the start condition, which is a high to low transition of SDA when SCL is high. Stop Condition All communications are terminated by a stop condition, which is low to high transition of SDA when SCL is high. Clock and Data Conventions Data states on the SDA line can change only during SCL SDA SCL START BIT BIT 0 BIT 1 … … BIT 4 WORD GAP STOP BIT Figure 1: Data Transmission Rev. 1 No Symbol/command MSB B3 B2 B1 LSB HEX 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 0 1 2 3 4 5 6 7 8 9 a b c d * # Pause Temporary MF select Recall 1 0 0 0 1 1 1 0 0 0 0 1 0 1 1 1 1 1 0 1 0 0 0 0 0 0 1 1 1 0 0 1 1 1 1 1 1 0 1 0 1 0 0 1 0 0 1 0 1 1 1 1 0 0 0 0 0 0 0 0 1 0 0 1 0 0 1 1 1 1 1 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1C 00 04 02 10 14 12 08 0C 0A 06 16 0E 1E 18 1A 1B 19 01 20 21 22 23 24 25 26 27 28 29 30 31 32 LS on LS off MT on MT off 2nd on 2nd off Set Clock Start Start copy Start FIFO Start timer Blank all Test mode 0 0 1 0 0 1 0 0 0 1 1 1 1 0 0 0 1 0 1 1 1 1 0 0 1 0 1 0 0 0 1 1 0 1 1 0 1 1 1 0 1 0 0 1 1 1 0 1 1 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 05 03 11 09 07 1F 0B 0D 0F 13 15 1D 17 6 Jan. 1995 Data Sheet AS2574B Key Combinations Key/Key Combination Function Remarks ENTER Programming R Flash or ground loop MEM Abbreviated dialling MUTE Privacy mute Code no 22/23 LS Monitor/Handsfree Code no 20/21 LNR Last Number Redial Code no 19 During execution of a pause the LNR key is used to terminate the pause. M1 - 10 Direct memory keys 2nd Second functions Code no 24 2nd, 1 a Code no 11 2nd, 2 b Code no 12 2nd, 3 c Code no 13 2nd, 4 d Code no 14 2nd, * Enter FIFO Code no 29 2nd, # Pause Code no 17 2nd, M1 - 10 Memories 11 - 20 MEM, 0 - 9 Memories 11 - 20 ENTER, Address* Displaying content of Memo ENTER/Address* Programming Code no 28 when both keys are released ENTER/# Setting clock Code no 26 2nd, 5 - 9 5-9 2nd, 0 0 Code no 1 2nd, R RECALL Code no 19 2nd, MUTE Privacy MUTE Code no 22/23 ENTER/LNR Clearing LNR Code no 27 ENTER, ENTER Displaying Access code Code no 27 Code no 6 - 10 *) Address means M1 - 10 keys or 2nd, M1 - 10 or MEM, 0 -9 key combinations. Rev. 1 7 Jan. 1995 Data Sheet AS2574B Diode Options Option Column NoP 1 Function Number of Pulses Digit 1 2 3 4 5 6 7 8 9 0 No diode diode Standard 1 2 3 4 5 6 7 8 9 10 NZ 9 8 7 6 5 4 3 2 1 10 101.2 ms 600 ms 10 20 33/66 ms 40/60 ms FT 2 Flash Time MS 3 Memory Size M/B 4 Make/Break Ratio ACP 5 Automatic Call Progress no yes MODE 6 Default Signalling Mode MF LD The diode options are scanned by POR and low to high transition on HS. Columns 1 2 3 4 5 6 Row 5 NoP FT MS M/B MODE Furthermore, it is also possible to invoke the CPM by pressing the LNR, MEM or M1 - 9 when the ACP (Automatic Call Progress) is activated (diode 5). System Considerations The device is intended to be used in telephone instruments, that are permanently on-line, i.e. also when onhook the circuit is connected to the telephone line, but in standby mode (idle) and hence only drawing a small leakage current from the line. Procedure Principles The procedures for utilizing the features of the device are optimized out of consideration for the human factor in order to: - meet the user´s expectations - be easy to learn and relearn - not invoke any automatic functions which the user doesn’t expect - protect the user from committing critical errors, e.g. dialling wrong numbers, deleting stored numbers, etc. - be consistent, simple and usable. This implementation offers new features like electronic hook switch and call progress monitoring (on-hook dialling). Call progress monitoring (CPM) means pressing the LS key will switch the telephone on from standby (direct ´wake-up´from keyboard) and will present the dialling tones via a loudspeaker without lifting the handset. Rev. 1 ACP 8 Jan. 1995 Data Sheet AS2574B Symbols Idle Idle Standby state, no keys activated Off-hook Lifting handset (HS = High) or pressing LS key On-hook Replacing handset (HS = Low) or repressing LS key Manual Dial Idle Idle Off-hook Key in digits Entries stored in LNR RAM Entries are dialled out Speech mode On-hook Idle The last manually dialled number is automatically stored in the LNR RAM. In LD mode * invokes temporary MF mode and # are ignored. In MF mode * and # are automatically stored in LNR RAM. Rev. 1 9 Jan. 1995 Data Sheet AS2574B Programming/Notepad Speechmode mode Speech or idle During programming the dial out is inhibited. Enter correction Key in an address Key in number no change Content of selected memory is displayed Digits are entered in LNR RAM Enter Enter keep Enter depressed Direct dial (M1 - 10) Access code(s) are displayed Digit 0 (access codes) 2nd MEM Direct dial (M11 - 20) Digit 0-9 (M11 - 20) release Enter stored Code no 28 The content of the LNR RAM is stored in the selected memory. Speechmode mode Speech or idle 10 Direct dial keys, a MEM and a 2nd key are available for addressing up to 20 numbers. Each number can contain up to 18 digits, including recall and pauses. Programming a new number will automatically clear the previous. 2nd, # has to be pressed between the different access codes. Rev. 1 10 Jan. 1995 Data Sheet AS2574B Direct Dial/Abbreviated Dial/Last Number Redial Idle N Y HS = High Off-hook D D Y Diode 3? N MEM Digit 0 - 9 (M11 - 20) D 2nd D Direct dial (M11 - 20) D Direct dial (M1 - 10) Pause 4 sec DIALLING Terminate pause Reset timer N LNR D Hi-Z Y DT high ≥ 1.15 sec D H Y DT pin Pause N L All digits dialled ? Executing pause Starting timer N Y Speech mode N Timer overflow Postdialling available Y Rev. 1 11 Jan. 1995 Data Sheet AS2574B Automatic Call Progress (ACP) Idle (Diode 5 inserted) D Y Diode 3? N MEM Direct dial (M1 - 9) D Off-hook Off-hook Start timer Start timer Y D Off-hook Off-hook Start timer Start timer LNR D Off-hook Off-hook Start timer Start timer Time-out 8 sec N Digit 0 - 9 (M11 - 20) D Time-out 8 sec Y N Y N DT high ≥ 1.15 sec Reset timer Dialling Pause 4 sec Terminate pause Reset timer Hi-Z H Y DT pin Pause N L All digits dialled ? Executing pause Starting timer N Y Speech mode Timer overflow N Postdialling available Y Rev. 1 12 Jan. 1995 Data Sheet AS2574B Privacy Mute MT output will go low. (code 23) Speech mode Dialling Change of hook state Mute key (code 22) Speech mode MT high Mute key (code 23) MT output will go low. Speech mode Rev. 1 13 Jan. 1995 Data Sheet AS2574B Temporary MF Select Speech mode LD default * Speech mode MF selected Key in digits Rev. 1 All further entries are NOT stored in LNR RAM but buffered in FIFO. The LNR RAM will contain the number entered before pressing the * key and the mode change code. Recall On-hook LD default Idle Key in digits Off-hook LD default Speech mode LD default 14 Jan. 1995 Data Sheet AS2574B Setting Clock (in display driver) Speechmode mode Speech or idle keep Enter Enter depressed keep keepEnter Enter depressed depressed Press # __:__ release Enter keep Enter Enter depressed Key in hours (2 digits) 18:__ Key in min. (2 digits) 18:31 Speech Speechmode mode or oridle idle Rev. 1 15 Jan. 1995 Data Sheet AS2574B Hook States 1) N Idle Diode 5? On-hook Off-hook Automatic Call Progress (ACP) Monitor or Handsfree 2) LS M LS POT Y ( ) 5) Dialling finished LS POT + Monitor 1) 2) 3) 4) 5) LS N Y Pressing any unvalid key doesn´t have any effect in Idle state. POT means Plain Ordinary Telephone. Lift handset means HS going high. Replace handset means HS going low. Lifting the handset during ACP will change the hook state to POT, however, the dialling will continue uneffected. Rev. 1 16 Jan. 1995 Data Sheet AS2574B Timing Diagrammes The timing diagrammes do not show the correct scaling only the sequence. P.O.T. < 2 sec. 2 sec. CD HS DP Whole keyboard enabled Diode scanning Monitor State < 2 sec. 2 sec. CD ιι LS key ιι DP ιι Whole keyboard enabled < 2 sec. 2 sec. Rev. 1 CD ιι LS key ιι DP ιι 17 Jan. 1995 Data Sheet AS2574B LD Dialling Osc Key entry 2 1 MT MR Tho Mask DP Tidp Tb Tb Tpre Tm Tpo Tidp Tb Tpre Tpo = depending on Mute key (high when Mute key has been activated, otherwise low) MF Dialling Osc Key entry 2 3 1 MT MR Mask Tone DP Tmo Ttd Titp Tho Tmo Tho = depending Mute key (high when Mute key has been activated, otherwise low) Rev. 1 18 Jan. 1995 Data Sheet AS2574B Flash Osc Key entry R MT MR Tho Mask DP Tpre GL Tfd Tpo Pause = depending on Mute key (high when Mute key has been activated, otherwise low) Ground Loop (GL) Osc Key entry R MT MR Tho Mask DP GL Tgl Pause Tpre Tpo = depending on Mute key (high when Mute key has been activated, otherwise low) Rev. 1 19 Jan. 1995 Data Sheet AS2574B Automatic Dialling LD (content of LNR is GL, 2, 1 and GL is stored as access code) Osc Key entry LNR MT MR Mask DP GL Pause Tap Tidp Tho Tpo = depending on Mute key (high when Mute key has been activated, otherwise low) Automatic Dialling MF (content of LNR is Flash, 1, 2, 3, and Flash is stored as access code) Osc Key entry LNR MT MR Mask DP GL Tone Pause Tap Tmo Tpo = depending on Mute key (high when Mute key has been activated, otherwise low) Rev. 1 20 Jan. 1995 Data Sheet AS2574B Electrical Data Absolute Maximum Ratings Positive Supply Voltage ...................................................................................................................-0.3V ≤ VLS ≤ 7V Input Voltage .......................................................................................................................-0.3V ≤ VIN ≤ VDD + 0.3V Input Current ................................................................................................................................................± 25 mA Storage Temperature ......................................................................................................................-65°C to +125°C Electrostatic Discharge (HBM) ......................................................................................................................±1000V Recommended Operating Range Parameter Symbol Min Operating Temperatur Top - 25 Operating Voltage VDD 2.5 Retention Voltage VDD 1.8 Oscillator Frequency Typ 3.0 Fosc Max Unit 70 °C 5.5 V 5.5 V 681 Condition kHz DC Characteristics Default conditions: Recommended Operating Range; VDD = 3.0V. Parameter Supply Current Operating except MF Operating MF Symbol Min Typ Max IDD Unit Condition Outputs unloaded Data Retention 200 0.75 250 1 µA mA 1 2 2 4 µA µA VDD=1.8V; note1 Note 1 Input Voltage Low Vil VSS 0.3xVDD V High Vih 0.7xVDD VDD V 1 1 µA µA Input Current Low High Iil Iih Output Current Sink Iol 1.5 mA Vol = 0.4V Ioh 1 mA Voh = VDD - 0.4V Rhs Rcd 1 1 MΩ MΩ Source Pull-down Resistor HS Input CD Input Scanning Current DT During Pause Sink Isl 20 150 µA Source Ish 20 150 µA Note 1: Circuit in Idle state (HS = Low and no key activated). Rev. 1 21 Jan. 1995 Data Sheet AS2574B Signalling Characteristics Defaults conditions: Recommended Operating Range Parameter Symbol Clock Startup Time Ts Key Debounce Time HS Debounce Time Td Ths CD Reset Delay Time DTMF Tone Level, High Group Preemphasis Distortion Tone Duration Inter Tone Pause Tone Rise/Fall Time LD Dial Rate Make/Break Period (diode option) Inter Digit Pause Pre Digit Pause Post Digit Pause Flash Duration Typ 14 21 Tr Max Unit 5 ms 18 26 ms ms 2 Condition sec Vol - 12.4 2 - 10.9 2.5 - 9.4 2.8 - 26 dBm dBm dBr Ttd Titp Ttr 80 80 82.3 82.3 85 85 5 ms ms ms Note 1 Note 1 Note 2 ± 5% ± 5% ± 5% 785 57 57 pps ms ms ms ms ms 103 620 ms ms No diode 2 With diode 2 510 ms 10 33/66 40/60 Tm/Tb Tidp Tpre Tpo 753 55 55 Tfd 100 600 Earth Recall Duration Tg Automatic Access Pause Short Long Termination Tap Mute Overhang MR/MT Hold Over Tone Burst Frequency Output Level Tone Duration Inter Tone Pause (LS) Inter Tone Pause (Mute) Time-out Min 101.2 500 4 7.9 1.15 4.1 8 1.2 4.2 8.1 1.25 sec sec sec Tmo Tho 182 18 200 223 27 ms ms Fb Vtb Ttb Titb1 Titp2 700 -13 80 7 1.8 8 2 800 -9 85 9 2.2 Hz dBm ms sec sec Tto 7.7 8 8.2 sec -11 RL = 15 kΩ RL = 15 kΩ RL = 15 kΩ, note 3 DT = Hi-Z DT = Low DT = High Note 1: The values are valid during automatic dialling and are minimum values during manual dialling, i.e. the tones will continue as long as the key is depressed. Note 2: The rise time is the time from valid key detection (key has been debounced) till the tone amplitude has reached 90 % of its final value. Note 3: Relative to high group. Rev. 1 22 Jan. 1995 Data Sheet AS2574B Pin Configuration 28 Pin DIP 28 Pin SOIC OSC2 1 28 OSC1 OSC2 OSC1 Vdd TONE 28 Vdd TONE SCL TB Vss SCL TB SDA Vss SDA C1 C1 HS C2 DP C2 C3 C3 DP DT DT ER C4 ER C5 C5 C6 MT MR R1 CD C6 R1 R2 R2 MASK R3 LS R4 14 15 HS C4 MT MR CD MASK R3 R4 14 15 LS R5 R5 Ordering Information Part number AS2574B P AS2574B N TB TONE Vdd OSC2 OSC1 SCL SDA 28 Pin PLCC C4 DT C5 ER C6 MT R1 MR Package 28 pin DIL 28 pin PLCC CD DP MASK C3 LS HS R5 C2 R4 Vss R2 R3 C1 Rev. 1 1 23 Jan. 1995 Data Sheet AS2574B Devices sold by Austria Mikro Systeme are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. Austria Mikro Systeme makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. Austria Mikro Systeme reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with Austria Mikro Systeme for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-sustaining equipment are specifically not recommended without additional processing by Austria Mikro Systeme for each application. Copyright 1995, Austria Mikro Systeme International, Schloss Premstätten, 8141 Unterpremstätten, Austria. Trademarks Registered. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. Rev. 1 24 Jan. 1995