Data Sheet

Rev. 3

20

AS2578 /B

March 1997

ACCharacteristicsCont´d

Symbol

Parameter

Conditions

Min

Typ

Max

Units

DTMF

V

MF

MF Tone Level

High group, R

-12.3

-10.8

-9.3

dBm

∆V

L-H

Preemphasis Low to High

R

2.0

2.4

2.8

dB

THD

Distortion (0.3 - 4 kHz)

R

-23

dBr

t

TD

Tone Duration

Note 1

80

82.3

85

ms

t

ITP

Inter Tone Pause

Note 1

80

82.3

85

ms

t

TR

Tone Rise Time

Note 2

5

ms

t

TF

Tone Fall Time

Note 2

5

ms

LD

t

DR

Dial Rate

±5%

10

pps

t

M/B

Make/Break Period

±5%, MODE = low

40.8/61.2

ms

±5%, MODE = high

33/66

ms

t

IDP

Inter Digit Pause

800

840

880

ms

t

MO

Mute Overhang

t

M

t

FD

Flash Duration

100

102

ms

t

GLS

Ground Loop, Short

R key

≤ 540 ms

495

500

505

ms

t

GLL

Ground Loop, Long

R key > 540 ms

1200

1250

1300

ms

t

AP

Automatic Pause

2.9

3.0

3.1

sec

Melody

V

MO

Melody Output

PDM

t

MD

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

Detection Time

80

85

ms

t

TO

Detection Time-out

note 4

ms

f

MIN

Min. Detection Frequency

19

20

21

Hz

f

MAX

Max. Detection Frequency

58

59

60

Hz

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 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

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.