SA541
SA541
10
9
4
5
12
3
and
6
7
11
1
2
13
14
15
20
16
17
18
19
8
-
SA54L1
10
9
4
5
14
3
6
7
13
1
2
15
16
17
22
18
19
20
21
8
11
Designation
V
DD
V
SS
OSC OUT
OSC IN
MUTE
MASK
FILT IN
FILT OUT
MF OUT
IMP
SELECT
C1
C2
C
C4
R1
R2
R3
R4
HSW
LOCK
Description
Positive Supply input
Negative Supply input
Connections for 560KHz ceramic resonator
Active high output during keying, tone transmission and
MUTE key depression. (See Note 1)
Output to disable speech circuit during pulse dialling
recall. (See Note 2)
Unity gain amplifier input and output for DTMF tone
filtering
DTMF output
'Loop disconnect' dialling output.
LD/DTMF selection, IDP and B:M ratio programming
Column output connections for 16 button single contact
keypad
Row input connections for 16 button single contact
keypad
Hookswitch input. A logic 1 (High) indicates an “off-
hook” condition
Lock Input must be tied to V
SS
to disable all keypad keys
(except TBR, LNR and MUTE). Normal operation is
enabled by connecting LOCK to V
DD.
No connection
-
12
N/C
Note 1: The MUTE output is provided to disable the microphone while maintaining the
loop condition during DTMF transmission.
Note 2: The MASK output may be used to disconnect the whole speech circuit in order
to mantain the break condition whilst on-hook, during a Timed Break Recall
(TBR) operation or LD dialling.
Table 1: Pin Description
6/16
sames
SAMES [ SAMES ]
