SA2532KA Datasheet, PDF (7/21 Pages) Sames – SINGLE CHIP TELEPHONE FOR INDIA

SA2532KA/B
Moving Cursor Procedure
To accommodate easy and uncomplicated redialling
(LNR) behind a PABX, a sliding cursor protocol is
implemented. If new entries match the previous
RAM contents, pressing the LNR key will dial out
the remaining digits. If there is an error in matching,
the LNR will be inhibited until next on-hook, and the
RAM will contain the new number. In the case of
mixed mode LNR operation the redialling in the
SA2532KA is limited to the LD digits so as to
prevent unauthorised access to banking passwords
etc. The SA2532KB will dial out all digits (i.e. both
the pulse and the DTMF digits) during mixed mode
re-dialling.
DTMF Tones
The DTMF generator provides 7 frequencies,
namely:
Low group
Digit 1-2-3
Digit 4-5-6
Digit 7-8-9
Digit *-0-#
697Hz
770Hz
852Hz
941Hz
High group
Digit 1-4-7-*
Digit 2-5-8-0
Digit 3-6-9-#
1209Hz
1336 Hz
1477Hz
The MF output levels are -6/-8 dBm and the
preemphasis is 2.6dB.
Tone Ringer
The Tone Ringer of the SA2532K incorporates a
Discriminator Circuit and a three tone Melody
Generator.
When a Valid Ring Signal is detected the Melody
generator is activated and creates a ringing signal
comprising 3 frequencies F1 (1065Hz), F2
(1420Hz) and F3 (1734Hz).
These frequencies are repeated in a sequence of 6
time slots constructed by the frequencies
F1 F2 F3 F1 F2 F3
This sequence is repeated 7 times per second.
Ring Frequency Discrimination
The Ring Frequency Discriminator assures that
signals with a frequency between 13 Hz to 70 Hz
are regarded as valid ring signals. When a valid ring
signal is detected, the melody generator is activated
and remains active as long as the ring signal is
present. Once the melody generator has been
started, the ring signal is continuously monitored
and the melody generator is instantly turned on or
off according to the momentary presence of a valid
or invalid ring signal respectively (until next POR of
off-hook).
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