SA545 Datasheet, PDF (11/18 Pages) Sames – PULSE/DTMF SWITCHABLE DIALLERS WITH 10 REPERTORY MEMORIES

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
sames
11/18