SA541 Datasheet, PDF (12/16 Pages) Sames – PULSE/DTMF SWITCHABLE DIALLERS

SA541
DTMF Mode Timing Diagram
Figure 4: DTMF Mode Timing Diagram
10. Loop Disconnect Dialling (Figures 5 and 6)
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
remains at logic '0'.
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