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PCD3310AT

Pulse and DTMF diallers with redial

Philips Electronics 

Philips Semiconductors

Pulse and DTMF diallers with redial

Product specification

PCD3310; PCD3310A

8.2 Redialling

After CE has risen to VDD the oscillator starts running.

The address of the first digit in the redial register is stored

in the RAC, and the device is in the conversation mode.

If ‘R’ is the first keyboard entry the device starts redialling

the contents of the temporary register. If the overflow flag

of the TWAC was set in the previous dialling, the redialling

continues in the main register.

Because access to an external line from a PABX usually

involves dialling an access code and waiting for an access

tone, a ‘one-press’ redial may fail due to insufficient delay

between the access code and the external number.

For this reason, the access code should be redialled. If the

access code (up to 4 digits) matches the first part of the

stored number, then pressing R after the access tone is

obtained will cause the rest of the number to be redialled

(see Fig.7, PABX).

Timing in the DTMF mode is calibrated for both tone bursts

and pauses.

In mixed mode only the first part entered (the pulse dialled

part of the stored number) can be redialled.

During redial keyboard entries (function or non-function)

are not accepted until the device returns to the

conversation mode after completion of redialling. No redial

activity takes place if one of the following events occur:

• Power-on reset

• Memory clear (‘P’ without subsequent data entry)

• Memory overflow (more than 23 valid data entries).

8.3 Notepad

The redial register can also be used as a notepad. In the

conversation mode a number with up to 23 digits can be

entered and stored for redialling. By activating the program

key (P) the WAC and TWAC pointers are reset. This acts

like a memory clear (redial is inhibited). Afterwards, by

entering and storing any digits, redialling will be possible

after flash or hook-on and hook-off (see Fig.9).

During notepad programming the numbers entered will not

be transmitted nor is the mute active, only the confidence

tone is generated.

handbook, full pagewidth

23

addressed

through pointers

WAC or RAC

6

5

4

3

2

1

MAIN REGISTER

5

4

addressed

through pointers 3

TWAC or RAC

2

1

TEMPORARY REGISTER

write address counter (WAC)

read address counter (RAC)

ADDRESS COUNTER

TEMPORARY WRITE

ADDRESS COUNTER (TWAC)

MGE493

Fig.6 Program memory map.

1996 Nov 21

11

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