SA589 FAMILY

sames

10/14

TABLE 3: Tone Frequencies

Keypad

R1

R2

R3

R4

C1

C2

C3

C4

Nominal frequency (Hz)

697

770

852

941

1209

1336

1477

1633

Deviation from nominal (%)

-0.07

-0.10 +0.19 -0.15 -0.17

-0.20

-0.22

-0.31

NOTE:

There will be an additional frequency error caused by any deviation of the resonator

frequency from the nominal 560kHz.

LOOP DISCONNECT DIALLING

The MASK output is provided in order to disable the speech circuit during LD dialling.

Consequently the MASK output is normally at logic '1' in the off-hook condition, but changes

to logic '0' during LD dialling. MASK also changes to logic '0' in order to signal a Timed Break

Recall (Flash) to the line.

Both MUTE and MF OUT remain low during LD dialling. LD dialling is signalled on the IMP

output. A break is signalled by a logic '0'. Make periods and IDP times are signalled by a logic

'1'. When not dialling, the IMP output sits at logic '0'.

Fig. 6 LD mode timing diagram

KEY PRESS

COLUMN

ROW

MASK

IMP

MUTE(LOW)

MF OUT

"5"

"8"

"TBR"

"IDP"

2.2340

ON HOOK TIME OUT

HOOK SWITCH

"5"

"8"

DR-00688

"9"

(PARTIAL)

"9"