Datasheet AS2578P, AS2578N, AS2578BP, AS2578BN Datasheet (Austria Mikro Systeme International)

Data Sheet

AS2578 /B

TELEPHONE CONTROLLER WITH

Austria Mikro Systeme International



13 MEMORIES AND 2-WIRE BUS

Key Features

❑ Low operating voltage
❑ Low current consumption, standby ≤ 0.1 µA
❑ Oscillator using Xtal or ceramic resonator (3.58 MHz)
❑ Serial interface to external EEPROM
❑ Consistent, simple and usable procedures
❑ The settings are programmed via the keyboard and

stored in EEPROM or set by pin options

Dialler:

❑ Data protection with 20 digit FIFO
❑ Sliding cursor protocol with comparison
❑ Automatic pause generation
❑ Temporary MF select via keyboard
❑ 30 digit LNR (Last Number Redial)
❑ 13 x 20 digit memory (RAM) on chip

Tone Ringer:

❑ Ring frequency discrimination
❑ 3 tone melody with 4 different repetition rates
❑ Volume of melodies can be set in 4 steps

Package

Available in 28 pin DIP and PLCC.

General Description

The AS2578 /B are a versatile repertory LD/MF diallers
with a melody generator, a ring frequency discriminator
and a 2-wire interface to EEPROM. Together with the
AS2520/1, the AS2578 /B form a coherent basis for a
fully electronic telephone with a wide range of options.

The AS2578 /B are especially designed to adapt to
different PTT specifications. A RAM is on chip for last
number redial, 3 direct dial and 10 numbers with
abbreviated dialling. To allow easy use under a PABX,
the device incorporates automatic pause insertion and
sliding cursor procedure as selectable options (AS2578)
or centrex keys (AS2578B). The device can be used with
or without EEPROM as appropriate. When an EEPROM
is connected, all RAM content is stored in the EEPROM
by power loss.

The circuit provides the possibility to set different modes
of operation (LM codes) via the keyboard or via pin
options, e.g. default signalling mode, automatic pause
insertion, flash or ground loop and settings of volume
and melodies.

Block Diagramme

1

2

4

5

8

7

0

*

Vss VDD

(AS2578B)

MUTE

3
6

9

#

SET

LNR

R

M1

M2

M3

MEM

3.58 MHz

A
B

C
D

MASK

GL

MUTE

SCL

SDA

DP

KEYSCAN

OSCILLATOR

DIAL

SERIAL

INTERFACE

POR

REDIAL

13 X 20

1 X 30

RAM
FIFO

CONTROL

FREQUENCY

DETECTOR

HOOK

STATE

DTMF

MELODY

RING

HS

CE

MODE
AP (AS2578 only)

MV
RR

MF

MO

FCI

Rev. 3

AS2578 /B

1

March 1997

Data Sheet

Pin Description

Pin # Symbol Function

1C4Keyboard Columns
2C3
3C2
4C1

5HSHook Switch Input

This input is active high with internal pull-down resistor.

6 MODE Signalling (LD/MF) Default Mode Select Input

Mode pin Function
High LD default mode, make/break pulse 33/66 ms
Open MF only
Low LD default mode, make/break pulse 40/60 ms

7CEChip Enable Input

This input is active high with internal pull-down resistor and is used to initiate setup
procedures.

AS2578 /B

8 OSC2 Oscillator Input
9 OSC1 Oscillator Output

Oscillator pins for Xtal or ceramic resonator (3.58 MHz). When a ceramic resonator is used

a capacitor (10 - 22 pF) must be connected from each of the oscillator pins to VSS.
10 Vss Negative Power Supply
11 TONE DTMF Tone Output

The dual tones provided at this output have a level independent of the supply voltage in

the operating range from 2.5 to 5.5V.
13 SDA Serial Data I/O

SDA is a bidirectional pin with an open drain with internal pull-up resistor and is used to

transfer data into and out of a compatible EEPROM.
14 SCL Serial Clock Line Output

The SCL output is an open drain with internal pull-up resistor and is used to clock data into

and out of a compatible EEPROM.
15 FCI Frequency Comparator Input

Schmitt trigger input for ring frequency discrimination.
12 MO Melody Generator Output

Melodies for tone ringing are generated on this output. The output signal is PDM.
16 MUTE Mute Output

This push-pull output is high during dialling and when mute key has been activated,

otherwise low.
17 MASK Mask Output

This push-pull output is high during pulsing (make and break periods).

Continues…

Rev. 3

2

March 1997

Data Sheet

Pin Description cont´d

Pin # Symbol Function

18 DPN Dial Pulse Output

This is the push-pull output for controlling the hook-switch transistor. It is low during on-

hook and break periods and high during off-hook (see timing diagrammes).
19 GL Ground Loop Output

This push-pull output is high during ground loop
20 VDD Positive Power Supply
21 R4 Keyboard Rows

22 R3
23 R2
24 R1

25 C5 Keyboard Column (AS2578)

This column is for the memory keys

C6 Keyboard Column (AS2578B)

This column is for centrex keys (A - D keys). Automatic pause insertion and Temporary

MF select 1 are fixed enabled (AP open)

AS2578 /B

26 AP Access Pause Select Input (AS2578)

This input is used to select the automatic access pause insertion or sliding cursor (no

centrex keys):

AP pin Function
High Sliding cursor enabled Temporary MF select 2
Open Automatic pause insertion enabled Temporary MF select 1
Low Sliding cursor and pause disabled Temporary MF select 1

C5 Keyboard Column (AS2578B)

This column is for the memory keys
27 MV Melody Volume Select Input

This input is used to select the volume of the melodies in 4 steps by connecting the MV

pin to row 1, 2, or 3. Leaving the pin open is the default setting (max. volume).
28 RR Repetition Rate Select Input

This input is used to select the repetition rate of the melodies. 4 different rates can be

selected by either leaving the pin open (default) or connecting it to column 1, 2, or 3.

Note: "Open" means ≥ 100 kΩ.

Power On Reset

The on chip power on reset circuit monitors the supply
voltage (VDD). As long as VDD remains below the internal
reference voltage, Vref (typically 1.1V), the oscillator is
inhibited. When VDD rises above Vref (t
ms/V), a reset signal is generated to assure correct start­up.

= 1 µs/V to 50

RISE

Initial Setup

A low to high transition on the CE input will initiate an
automatic setup, i.e. the pin options are scanned and
(when an EEPROM is connected) the stored LM codes
and melody settings are read from the EEPROM. This is
done independently of the hook state (see timing
diagrammes).

Rev. 3

3

March 1997

Data Sheet

AS2578 /B

Valid Keys

The keyscanning is enabled when CE or HS are high.
During setup the keyboard is disabled. 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.

Mute Key

The mute key is only enabled when off-hook. Depressing
the mute key activates and deactivates (toggle switch)
the MUTE output, when internal mute is inactive, i.e. in
speech mode.

Any key entry overwrites a mute activated by the mute
key, and mute will be deactivated.

Centrex Keys (AS2578B only)

The alphameric keys accommodate easy use of centrex
services. The A, B, C and D keys are only valid in MF
mode and are not storable. Pressing one of these keys
will invoke the appropriate MF tones to be transmitted.
The centrex keys are not stored in the RAM, but are
buffered in the FIFO, and subsequently entered digits
are also buffered in the FIFO.

Pressing the recall key after a sequence including centrex
keys will reset the RAM counter, and subsequently
entered digits will be stored in the RAM. If MF select (Set,
* , Set) has been invoked once, then all susequently
digits/data will be buffered in the FIFO.

Memory Keys

The keys M1 to M3 are direct memory access keys and
the MEM key is used for abbreviated dialling.

13 numbers can be stored in on chip RAM. Each number
can contain up to 20 digits (including pauses).

If an EEPROM is connected to the serial bus, the content
of the RAM is written into the EEPROM when CE is
turned low indicating a power loss.

During programming multible pauses can be inserted by
pressing the LNR key.

Memory dialling is cascadable.

Mode Selection

The default mode (LD or MF) can be selected by the
MODE pin.

Furthermore, the mode can be selected by setting the
LM code (see setup menu). If no LM code is set, the
mode will be determined by the MODE pin.

When default LD mode is selected, a temporary change
to MF mode can be invoked by pressing * (AP = high,
AS2578 only) or Set, * , Set.

When the circuit is in temporary MF mode, each of the
following procedures revert it to default LD mode:

- pressing Set, * , Set ,

- pressing recall key (by further entries of the recall key
the signalling mode will toggle between MF and LD,

- by next On-hook.

Last Number Redial

LNR is a facility that allows resignalling of the last
manually dialled number without keying in all the digits
again. The LNR is repeatable.

The current contents of the RAM are overwritten by new
entries.

A manually entered number is automatically stored in the
LNR RAM. The capacity of the RAM is 30 digits. If a
number greater than 30 digits is entered, the LNR facility
will be inhibited (until new entries < 31 digits) and further
entries will be buffered in FIFO.

Postdialled digits, i.e. digits manually entered after LNR
has been invoked, are not stored in RAM but buffered in
FIFO.

Recall Function

A recall activation will invoke a flash (timed loop break)
or a ground loop (GL) depending on the selected LM
code, which is stored in the external EEPROM (see
setup menu).
If no LM code is set, depressing the recall key will invoke
both a flash and a GL, however, in LD mode a Flash is
never executed.

If recall is the first entry in a digit string, it will be stored
in LNR RAM when digit(s) are entered after the recall.

If the recall key is depressed after a digit string has been
entered or dialled out, the recall will not be stored, and
subsequently entered digits will be stored in the LNR
RAM as the new number.

If pressing the recall key is not followed by digit entries,
the LNR RAM remains intact.

Rev. 3

4

March 1997

Data Sheet

AS2578 /B

After a recall a pause will automatically be generated.
The pause time is 3 sec.

The ground loop (GL) has two pulse lengths, namely a
short of 500 ms and a long of 1250 ms.

Short GL: If the recall key is depressed for ≤ 540 ms, the
GL pulse is 500 ms.

Long GL: If the recall key is depressed for > 540 ms, the
GL pulse is 1250 ms.

During redial a ground loop is only executed as a long GL
(1250 ms).

Pause Generation

Pause introduces a delay in signalling digit strings to
accommodate second and subsequent dial tones.

Automatic pauses are generated in the following manner:

- always after a recall independent of the AP pin

- with automatic pause insertion enabled by pin option
or LM code, up to two pauses can be automatically
inserted at any location of the original entry in the RAM
(except location 1 of the digit string), when the mute
output goes inactive (in MF mode for more than 1 sec.)
before next entry.

A pause read from the RAM can be terminated (shortened)
prior to time out by a low level on AP pin (AS2578 only)
during the pause execution. The pause time is 3 sec.

During execution of a pause, mute is inactive, i.e. the
circuit is in speech mode.

Sliding Cursor Procedure (AS2578 only)

To accommodate redialling (LNR) behind a PABX without
using automatic pause generation, a sliding cursor
protocol is implemented. The sliding cursor is enabled
when AP = high. If new entries match the previous RAM
contents, pressing the LNR key will dial out the remaining
digits.

If there is an error in matching, the LNR will be inhibited
until next on-hook, and the RAM will contain the new
number.

Serial Interface

The AS2578 /B support a bidirectional bus oriented

protocol. The protocol defines any device that sends
data onto the bus as a transmitter, and the receiving
device as the receiver. The AS2578 /B are controlling the
transfer and hence the master. The EEPROM being
controlled is the slave.

The AS2578 /B will always initiate data transfer, and
provide the clock for both transmit and receive operations.
Therefore, the protocol is for single master applications
only.

However, a temporary second master can be used to
write into the EEPROM when the AS2578 /B are supplied
and in idle state.

Clock and Data Conventions

Data states on the SDA line can change only during SCL
low. SDA state changes during SCL high are reserved
for indicating start and stop conditions (see figure 1 and

2).

Start Condition

All commands are preceded by the start condition, which
is a high to low transition of SDA when SCL is high. The
slave should continuously monitor the SDA and SCL
lines for the start condition and must not respond to any
command until this condition has been met.

Stop Condition

All communications are terminated by a stop condition,
which is low to high transition of SDA when SCL is high.
The stop condition is also used to place the slave in the
standby power mode.

Acknowledge

Acknowledge is a software convention used to indicate
successful data transfers. The transmitting device, either
master or slave, will release the bus after transmitting
eight bits. During the ninth clock cycle the receiver will
pull the SDA line low to acknowledge that it received the
eight bits of data (see figure 3).

The slave should always respond with an acknowledge
after recognition of a start condition and its slave address.
If both the device and a write operation have been
selected, the slave should respond with an acknowledge
after receipt of each subsequent eight bit word.

In the read mode, when the EEPROM has transmitted
eight bits of data, it should release the SDA line and
monitor the line for an acknowledge. If the AS2578 /B
respond with an acknowledge and does not generate a
stop condition, the EEPROM should continue to transmit
data. If the AS2578 /B do not respond with an
acknowledge, the EEPROM should terminate further

Rev. 3

5

March 1997

Data Sheet

AS2578 /B

data transmission and await the stop condition to return
to the standby power mode.

SDA

SCL

data

stable

data

change

Figure 1 Data Validity

SDA

SCL

start

bit

stop

bit

Figure 2 Definition of Start and Stop

Tone Generator

The tone generator incorporates the DTMF tones and 3
basic frequencies for the tone ringer.

DTMF

The DTMF generator provides 8 frequencies, namely:
Low group

Row 1 697 Hz
Row 2 770 Hz
Row 3 852 Hz
Row 4 941 Hz

High group

Col. 1 1209 Hz
Col. 2 1336 Hz
Col. 3 1477 Hz
Col. 6 1633 Hz (AS2578B only)

The MF tones are in accordance with CEPT
recommendations.

Tone Ringer (Melody)

The three basic frequencies of the melodies are:

SCL from
master

Data out
from Tx

Data out
from Rx

start

1 8 9

acknowledge

Figure 3 Acknowledge Response From Receiver

Frequency Comparator

The frequency comparator monitors that the ring signal
is in the limits as shown in figure 4.

MUST

DETECT

20 30 40 50 60

Tol.

Ring

frequency

70

(Hz)

F1 = 800 Hz, F2 = 1067 Hz, and F3 = 1333 Hz (± 5%).
The repetition rate can be set via key procedures or by

pin options as follows:
LM code Repetition rate

1 1 time (50 ms pause)
2 (default) 4 times

3 7 times
4 10 times

Repetition rate means that a sequence of 6 frequencies
is repeated 1 to 10 times within 1 sec. For LM code 1 a
pause of 50 ms is inserted between the frequencies to
allow a better recognition of the melodies.

The sequence of the frequencies is controlled by the
sequence register as follows:

Sequence F1 F2 F3 F1 F2 F3 …

The volume of the melodies (MO output) can be set as
follows:

Figure 4 Detection Window of Ringing Signal

When a continious valid ring signal is present for 80 ms,
the melody generator is activated and remains active
until two or more periods of the ring signal are missing.

Rev. 3

LM code Volume Steps

1 - 17.5 dB
2 - 11.5 dB 6 dB
3 - 5.5 dB 6 dB
4 (default) 0 dB 5.5 dB

6

March 1997

Data Sheet

LM Codes and Pin Options

LM code Pin option Function

02-2* AP = L Automatic pause insertion: off Sliding cursor: off MF select 1

02-3 AP = Hi-Z Automatic pause insertion: on Sliding cursor: off MF select 1

- AP = H Automatic pause insertion: off Sliding cursor: on MF select 2
033* MODE = L LD mode 40/60 GL
033* MODE = H LD mode 33/66 GL

036 - MF mode GL
037 - MF mode Flash

- MODE = Hi-Z MF mode GL + Flash

250 - Resets all user settings to default and clears all RAM contents
258 - Clears all RAM contents

5 - 4* MV = Hi-Z Melody volume: 0 dB

5 - 3 MV = R3 Melody volume: - 5.5 dB
5 - 2 MV = R2 Melody volume: - 11.5 dB

AS2578 /B

5 -1 MV = R1 Melody volume: - 17.5 dB

6 - 1 RR = Hi-Z Repetition rate: 1 time (50 ms pause)

6 - 2* RR = C1 Repetition rate: 4 times

6 - 3 RR = C2 Repetition rate: 7 times
6 - 4 RR = C3 Repetition rate: 10 times

Note 1: Programming an LM code overwrites pin options, however, LM code 033 can only be selected when the MODE

pin is connected to either high or low for selecting the make/break ratio. Not valid LM codes are ignored. LM

codes with a '*' are default settings.
Note 2: When the AP pin is pulled low during execution of a pause, the pause will be terminated.
Note 3: AP pin option not available on AS2578B.

Rev. 3

7

March 1997

Data Sheet

AS2578 /B

Operating Procedures

Procedure Principles

The procedures for utilizing the features of the AS2578 /B 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, etc.

- be consistent, simple and usable

- meet the German 1 TR 2 and ETR 2 specifications.

Symbols

States: Entries: Processing:

Idle (on-hook,
no ringing)

Ringing

Speech mode

Privacy mute

Programming

False programme
entry

KEY

TEXT

1590

Going off-hook

Going on-hook

Pressing a key

Entering a
number

Entry according
to text

Enter
password

X

TEXT

sec

or

Time out (x sec.)

Dialling
(LD or MF)

Storing (writing into
RAM or EEPROM)

Processing
according to text

Melodies activated
(ringing)

= reading from
memory

Rev. 3

TEXT

Invalid entry

State according
to text

8

March 1997

Data Sheet

AAA

Setup Procedures

AS2578 /B

SET

ANY OTHER

ENTRY

FALSE

ANY OTHER

ENTRY

ANY OTHER
SEQUENCE

LNR

1

1590

LNR

LM Codes

022 or 023 or

033 or 036 or 037

LNR

022, 023 executed.

033, 036, 037

buffered

*

Temporary MF Select

LNR

Clear

Procedures

SET

022, 023 executed.

033, 036, 037

buffered

5 or 6

Storing Direct Numbers

Programming Melody

LM Code

250

LNR

M1-3

Storing Indirect Numbers

MEM

LM Codes:

022 = no AP, no SC
023 = AP, no SC

033 = LD (MODE pin = V
036 = MF, GL
037 = MF, FL

250 = Resets all settings to default, inhibits LNR

and memories

258 = Inhibits LNR and memories

SET

Resets all

settings

to default

LM Code

258

LNR

DD or Vss), GL

SET

Rev. 3

Exit programme state

SET

sec

40

9

March 1997

Data Sheet

Clear Procedures

AS2578 /B

SET

ANY OTHER

ENTRY

ANY OTHER

ENTRY

ANY OTHER
SEQUENCE

LNR

1

LNR

*

Temporary MF Select

1590

Setup Procedures

LM Code

258

LNR

5 or 6

Storing Direct Numbers

Programming Melody

LM Codes:

258 = Inhibits LNR and memories

M1-3 MEM

SET

Storing Indirect Numbers

Rev. 3

Exit programme state

SET

40

sec

10

March 1997

Data Sheet

Programming Melody

AS2578 /B

SET

ANY OTHER

ENTRY

ANY OTHER

ENTRY

IGNORED

5 or 6

Key

1, 2, 3, or 4

SET

Executing

LM Code

Exit programme state

*

Temporary MF Select

LM Codes:

(5) 1 = Melody volume - 17.5 dB
(5) 2 = Melody volume - 11.1 dB
(5) 3 = Melody volume - 5.5 dB
(5) 4 = Melody volume 0 dB (default)

(6) 1 = Repetition rate 1
(6) 2 = Repetition rate 4 (default)
(6) 3 = Repetition rate 7
(6) 4 = Repetition rate 10

1

Setup Procedures

&

Clear Procedure

M1-3 MEM

Storing Direct Numbers

Storing Indirect Numbers

Rev. 3

SET

40

sec

11

March 1997

Data Sheet

Programming Volume of Melody During Ringing

AS2578 /B

RINGING

ANY OTHER

ENTRY

IGNORED

Key

1, 2, 3, or 4

Executing

LM Code

End of ringing

Only one change during a
ringing phase!

LM Codes:

1 = Volume - 17.5 dB
2 = Volume - 11.5 dB
3 = Volume - 5.5 dB
4 = Volume 0 dB (default)

Rev. 3

12

March 1997

Data Sheet

Temporary MF Select 1

(AP pin = open or low)

FIFO

Pressing any other key does not
change the state.

AS2578 /B

RAM

Set, * , Set

D

FIFO

R

2

FIFO

R

EXIT FIFO

Set, * , Set

1

FIFO

Set, * , Set

Rev. 3

13

March 1997

Data Sheet

Temporary MF Select 2 (AS2578 only)

(AP pin = high)

FIFO

Pressing any other
key does not
change the state.

Set, * , Set

AS2578 /B

RAM

*

D

FIFO

R

2

FIFO

R

Set, * , Set

EXIT FIFO

Set, * , Set

1

FIFO

*

Rev. 3

14

March 1997

Data Sheet

Automatic Dialling

AS2578 /B

MEM

0 - 9

or

M1-3

LNR

Rev. 3

Postdialled digits are not stored
but buffered in FIFO

15

March 1997

Data Sheet

Storing Numbers

AS2578 /B

SET

ANY OTHER

ENTRY

M1-3

M1-3

MEM

0 - 9

SET

*

Temporary MF Select

M1-3

MEM

MEMM1-3

5 or 6

Programming

Melody

1

Set Procedures

Rev. 3

CLEARS SAID

RAM MEMORY

LOCATION

Exit programme state

40 secSET

CLEARS SAID

RAM MEMORY

LOCATION

16

March 1997

Data Sheet

Privacy Mute

AS2578 /B

MUTE

Rev. 3

17

March 1997

Data Sheet

AS2578 /B

Electrical Characteristics

Absolute Maximum Ratings

Positive Supply Voltage...................................................................................................................-0.3V ≤ V

Input Current ................................................................................................................................................± 25 mA

DD

≤ 7V

Digital Input Voltage......................................................................................................V

- 0.3V ≤ VIN ≤ VDD + 0.3V

SS

Electrostatic Discharge (HBM)........................................................................................................................±800V

Storage Temperature......................................................................................................................-65°C to +125°C

Recommended Operating Conditions

Supply Voltage (except DTMF) .....................................................................................................2.2V ≤ VDD ≤ 5.5V

Supply Voltage (DTMF).................................................................................................................2.5V ≤ VDD ≤ 5.5V

Oscillator Frequency ..................................................................................................................................3.58 MHz

Operating Temperature....................................................................................................................- 25°C to +70°C

DC Characteristics (Default conditions: recommended operating conditions; outputs unloaded; VDD = 3.5V;

AP and MODE = Vss; unless otherwise specified))

Symbol Parameter Conditions Min Typ Max Units

I
I
I
I
V
V
I
I
R
R

DD0

DD

DD

DD

IL

IH

OL

OH

HS

CE

Standby Current HS = L; CE = L 0.1 µA
Standby Current HS = H; Osc. = 0 3.6 µA
Operating Current no tones 400 700 µA
Operating Current MF/melody 0.9 1.5 mA
Input Voltage, Low V
Line Voltage, High 0.8 V

SS

DD

0.2 V
V

DD

DD

V

V
Output Current, Sink VOL = 0.4V 1.5 mA
Output Current, Source VOH = VDD - 0.4V 1 mA
Pull-down Resistor 1 MΩ
Pull-down Resistor 1 MΩ

AC Charateristics (Default conditions: recommended operating conditions)
Symbol Parameter Conditions Min Typ Max Units

t

S

t

D

t

HS

t

SU

Clock Startup Time 5 ms
Key Debounce Time 14.7 ms
HS Debounce Time 14.7 ms
Setup Time 100 ms

Continues…

Rev. 3

19

March 1997

Data Sheet

AS2578 /B

AC Characteristics Cont´d
Symbol Parameter Conditions Min Typ Max Units

DTMF

V
∆V

MF

L-H

MF Tone Level High group, RL = 15 kΩ -12.3 -10.8 -9.3 dBm
Preemphasis Low to High RL = 15 kΩ 2.0 2.4 2.8 dB

THD Distortion (0.3 - 4 kHz) RL = 15 kΩ, note 3 -23 dBr
t

TD

t

ITP

t

TR

t

TF

Tone Duration Note 1 80 82.3 85 ms
Inter Tone Pause Note 1 80 82.3 85 ms
Tone Rise Time Note 2 5 ms
Tone Fall Time Note 2 5 ms
LD

t

DR

t

M/B

Dial Rate ±5% 10 pps
Make/Break Period ±5%, MODE = low 40.8/61.2 ms

±5%, MODE = high 33/66 ms
t
t

t
t
t
t

IDP

MO

FD

GLS

GLL

AP

Inter Digit Pause 800 840 880 ms
Mute Overhang t

M

Flash Duration 100 102 ms
Ground Loop, Short R key ≤ 540 ms 495 500 505 ms
Ground Loop, Long R key > 540 ms 1200 1250 1300 ms
Automatic Pause 2.9 3.0 3.1 sec
Melody

V

MO

t

MD

Melody Output PDM

Melody Delay 10 ms
F1 Frequency 1 770 800 830 Hz
F2 Frequency 2 1025 1067 1110 Hz
F3 Frequency 3 1280 1333 1385 Hz
t

DT

t

TO

f

MIN

f

MAX

Note 1: The values are valid during automatic dialling and are minimum values during manual dialling, i.e. the tones will
Note 2: The rise time is the time from 10% of final value till the tone amplitude has reached 90 % of its final value.

Note 3: Relative to high group.
Note 4: The FCI circuit is reset by POR and on-hook. After a reset the FCI circuit is in a standby state. A positive edge on FCI

Detection Time 80 85 ms

Detection Time-out note 4 ms

Min. Detection Frequency 19 20 21 Hz

Max. Detection Frequency 58 59 60 Hz

continue as long as the key is depressed.

will start the 73 ms timer and the frequency discrimination is initiated. Whenever a period of the ring frequency is
missing, the timer is reset. When a valid ring signal is present for ≥ 73 ms, the melody generator is started and is
directly controlled by a valid signal from the FCI circuit. This condition will remain until a new reset.

Rev. 3

20

March 1997

Data Sheet

Pin Configurations

AS2578 /B

C4
C3
C2
C1

HS

MODE

CE

OSC2
OSC1

Vss

TONE

MO

SDA
SCL

1
2
3
4
5
6
7
8
9
10
11
12
13
14

28
27
26
25
24
23
22
21
20

AS2578

19
18
17
16
15

RR
MV
AP
C5
R1
R2

R3
R4

V

DD

GL
DP
MASK
MUTE

FCI

28 Pin DIP

C4
C3
C2

C1

HS

MODE

CE

OSC2
OSC1

Vss

TONE

MO

SDA

SCL

1
2
3
4
5
6
7
8
9
10
11
12
13
14

28
27
26
25
24
23
22
21
20

AS2578B

19
18
17
16
15

RR
MV
C5
C6
R1
R2

R3
R4

DD

V
GL

DP
MASK
MUTE

FCI

HS

MODE

CE
OSC2
OSC1

Vss

TONE

Rev. 3

C1

C2

C3

C4

RR

1

AS2578

MO

SDA

SCL

FCI

MUTE

MV

AP

DP

MASK

C5
R1
R2
R3
R4
V

DD

GL

28 Pin PLCC

21

HS

MODE

CE

OSC2
OSC1

Vss

TONE

C4

C1

C2

C3

RR

MV

1

AS2578B

MO

SDA

SCL

FCI

MUTE

MASK

C5

C6
R1
R2
R3
R4
VDD

GL

DP

March 1997

Data Sheet

Ordering Information:

Part Number Package Pin 25 Pin 26

AS2578 P 28 pin DIP C5 AP
AS2578 N 28 pin PLCC C5 AP
AS2578B P 28 pin DIP C6 C5
AS2578B N 28 pin PLCC C6 C5

Applications:

For application support contact your local AMS sales office.

AS2578 /B

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
Mikro Systeme for each application.

Copyright  1995-7, Austria Mikro Systeme International AG, 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. 3

22

not

recommended without additional processing by Austria

March 1997