SA5453 Ver la hoja de datos (PDF) - South African Micro Electronic Systems

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SA5453

PULSE/DTMF SWITCHABLE DIALLERS WITH 10 REPERTORY MEMORIES

South African Micro Electronic Systems 

SA545

7. Earth Loop Recall (ELR) / Timed Break Recall (TBR) (Timed Flash)

The SA545 supports both TBR and ELR and offers a common operating protocol in

both cases.

After a Recall (Flash) operation, the dialling mode selected via the SELECT pin will

be restored. Only the digits dialled after the ELR/TBR operation will be retained in

the LNR store.

A TBR of 100ms1) is generated when the TBR key is pressed. The MASK output

goes low in order to produce the line break. When in DTMF mode, the MF OUT

output also goes low for the duration of the break.

ELR is supported via the C3 pin. If this pin is connected to ground for a minimum

of 20ms during an ELR operation, the chip will offer the same operating protocol as

for TBR.

The ELR function may be achieved by use of the circuit shown in Figure 2, or by use

of a double contact switch.

1) Other periods avaiable on request.

Figure 2: Earth Loop Recall Application

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