
South African Micro Electronic Systems
FEATURES
■ Selectable Loop-disconnect (Pulse) or DTMF (Tone) dialling modes
■ 10 x 24 Digit Repertory Dialling Stores
■ 24 Digit Last Number Redial (LNR)
■ Selectable Interdigit Pause (IDP) 500ms or 800ms
■ Operates with inexpensive single contact keypad
■ On-chip Darlington transistor pair for DTMF tone filtering
■ Low power CMOS technology enables direct operation from Telephone line
■ Keypad switchable Loop-Disconnect to DTMF during a call
■ Selectable Break:Make Ratios 2:1 or 3:2
■ Uses inexpensive 560KHz ceramic resonator
■ Earth Loop Recall and Timed Break Recall (Timed Flash)
■ Low on-hook Supply Current Options SA54X53 - 5µA @ 2.5V SA54X56 - 1µA @ 2.5V SA54X59 - 1µA @ 3.0V
■ Call, barring/locking feature available on the SA54L5
■ Optional use of external capacitor for oscillator