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SA545

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SA545

SA54L5

Designation

Description

10

10

V

DD

Positive Supply input

99

V

SS

Negative Supply input

4

4

OSC OUT

Connections for 560KHz ceramic resonator

5

5

OSC IN

12

14

MUTE

Active high output during keying and tone transmission.

(See Note 1)

3

3

MASK

Output to disable speech circuit during pulse dialling

and recall. (See Note 2)

6

6

FILT IN

Unity gain amplifier input and output for DTMF tone

7

7

FILT OUT

filtering

11

13

MF OUT

DTMF output

1

1

IMP

'Loop disconnect' dialling output. During dialling, a

logic 1 (high level) correponds to loop connection while

a logic 0 (low level) corresponds to loop disconnection.

2

2

SELECT

LD/DTMF selection, IDP and B:M ratio programming

13

15

C1

Column output connections for 16 button single contact

14

16

C2

keypad

15

17

C3

20

22

C4

16

18

R1

Row input connections for 16 button single contact

17

19

R2

keypad

18

20

R3

19

21

R4

8

8

HSW

Hookswitch input. A logic 1 (High) applied to this input

indicates an "off-hook" condition.

-

11

LOCK

Lock Input must be tied to V

(except TBR and LNR). Normal operation is enabled by

connecting LOCK to V

DD.

-

12

N/C

No connection

Note 1: The MUTE output is provided to disable the microphone (via the speech

network) 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 maintain the break condition whilst on-hook, during a Timed Break Recall

(TBR) operation or LD dialling.

Table 1: Pin Description