SA2532KA Datasheet, PDF (6/21 Pages) Sames – SINGLE CHIP TELEPHONE FOR INDIA

SA2532KA/B
RETURN LOSS
SIDE TONE
LINE
RI
R1
LI
SYN
R2
Z
REF
R5
STB
Z^BAL
V_SS
ONE COMMON GROUND
Figure 3
Double balanced bridge (return loss and side tone)
with one common ground
Dialling Functions
Valid Keys
The keypad of the SA2532K comprises a maximum
of 19 keys. A Bi-polar scan technique is used so
that the 19 keys are scanned in a partial 4 x 6
matrix using only 8 pins and 2 diode. The key
scanning is enabled when HS/DPN is pulled high
and V_DD is above V_REF. A valid key is detected when
one and only one contact closure is detected
between a Row and Column Pin. Key contacts are
debounced to avoid incorrect detection. It is also
possible to connect a controller to the rows and
columns.
Dial Mode Selection
The default mode (LD or MF) can be selected by
the Mode pin. When default LD mode is selected, a
temporary change to MF can be invoked by
pressing the * key. Once in MF mode the MODE
OUT pin becomes active. The circuit will revert to
LD by pressing either one of the Recall keys or by
next on-hook.
When MF mode is selected by the mode pin, the
circuit can not be changed temporary to LD but will
remain in MF. In LD mode the speech circuit will be
muted for the duration of the IDP.
Last Number Redial
LNR is a facility that allows re-signalling of the last
manually dialled number without keying in all the
digits again. The LNR is repeatable. A manually
entered number is automatically stored in the LNR
RAM. The capacity of the LNR RAM is 31 digits. If
a number greater than 31 digits is entered, the LNR
facility will be inhibited (Until new entries < 32 digits)
and further entries will be buffered in a First In First
Out Memory (FIFO). Post dialled digits, i.e. digits
manually entered after LNR has been invoked, are
not stored in RAM but buffered in FIFO.
Pauses can be inserted by pressing the PAUSE
key. Each pause is 2 seconds when inserted within
the first 5 digits otherwise a wait function will halt
dialling until PAUSE or LNR key is depressed.
Recall Function
A Recall activation will invoke a Flash (Timed Loop
Break).
If Recall is the first entry in a digit string, it will be
stored in LNR RAM when digit(s) are entered after
the Recall.
If the recall key is depressed after a digit string has
been entered or dialled out, the recall will not be
stored but buffered in the FIFO together with
subsequently entered digits.
If pressing the recall key is not followed by digit
entries, the LNR RAM remains intact. After a recall
a 274ms second pause will automatically be
executed.
Both Recall keys will be functional in both MF and
LD dialling modes.
Memory Keys
The single memory (M5) can be used to directly
access a stored number of not more than 21 digits.
During programming multiple pauses can be
inserted by pressing the PAUSE or LNR key. Each
pause is 3 seconds long when inserted within the
first 5 digits otherwise a wait function (infinite pause)
will be executed until the PAUSE or LNR key is
depressed
Mute Function
The MUTE key is enabled in speech mode only.
Depressing the MUTE key mutes the microphone
amplifier. Repressing the MUTE key deactivates
the mute (toggle function). Any key entry overwrites
a mute activated by the MUTE key and mute will be
deactivated.
When privacy mute is activated a reminder tone is
applied to the ear piece every 274ms.
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