SA589 FAMILY

sames

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TABLE 2: Dialling mode selection

Select Pin to

Dialling Mode

B:M Ratio

TBR (msec)

V

SS

LD + DTMF

2:1

100

COL1

LD + DTMF

2:1

270

COL2

LD + DTMF

3:2

270

COL3

LD + DTMF

3:2

100

COL4

LD only

2:1

-

COL5

DTMF only

-

270

COL6

DTMF only

-

270

COL7

LD only

3:2

-

V

DD

DTMF only

-

100

However, if one of the 'LD + DTMF' modes is selected the chip will be in LD mode initially in

the off-hook condition but may be switched to DTMF by pressing either *, */# or TONE key

(depending on the mask variant - see Fig. 2 and page 11), provided that dialling is not in

progress. If any of these keys are pressed during LD dialling, they will be ignored.

Only if * or # are pressed subsequent to switching to DTMF, will * or # be dialled. Only digits

entered prior to a switch to DTMF will subsequently be available for redialling (see Last

Number Redial operation), unless specified otherwise.

Once switched to DTMF, dialling will remain in this mode until either a Recall (Flash) operation

or until the chip returns to the on-hook state.

Last Number Redial (LNR)

The function of the on-chip LNR store is to retain automatically a manually dialled number for

redialling later. The capacity of the memory is 24 digits. If a number is dialled which is longer

than this, dialling will continue, but redialling will not be allowed with this number. To redial

a number in the LNR store, the LNR key may be pressed once, or the Redial key can be

pressed twice.

The last number redial store has several features designed to assist the user:

Moving cursor facility

This facility is provided to aid use in PABX applications, where the user must first dial an

access digit, or digits, and then wait for a second dial tone before continuing dialling.

This allows a user to enter the first digit or digits of the number in the last number redial store

manually before pressing the LNR key; the remainder of the number will be dialled when

the LNR key is pressed.

If the digit(s) dialled manually do not match those in the LNR memory, then redialling will

be inhibited for the remainder of the call, and the numbers entered will be saved in the LNR

memory for redialling in a subsequent call.

If the user manually dials the first digit(s) in the LNR memory, and then goes on-hook, the

whole contents of the memory will be retained.