5-4

Figure 2 - Pin Connections

Pin Description

Pin #

Name

Description

1

DET

Demodulator detection level adjust input (Analog). Internal resistor divider applies

2.36V in open circuit condition. Connection of external resistor will vary detect level.

2

CRx

3

RxI

4

RxE

Receive enable input (Digital) with internal pull up. Active high.

5

LOOP

Self-test mode select input (Digital) with internal pull down. Active high.

Internal reference supply voltage input (Analog) .

7

TxO

Modulated transmit carrier output (Analog).

8

TxDI

Transmit data input (Digital).

Negative power supply.

10

FATC

Tone caller center frequency adjust input (Analog).

11

TCO

Tone caller output (Digital).

12

MTC

Mute tone caller input (Digital) with internal pull down. Active high.

13

ETC

Enable tone caller input (Digital) with internal pull down. Active high.

14

CK32

32 kHz data strobe output (Digital).

15

OSC1

Clock Input

3.579545 MHz crystal connected between

these pins completes internal oscillator.

16

OSC2

Clock Output to drive external devices.

17

RxDO

Receive data output (Digital). Synchronized to CK32.

18

Positive power supply.

1

2

3

4

5

6

7

8

9

10

18

17

16

15

14

13

12

11

DET

CRx

Rxl

RxE

LOOP

VRef

TxO

TxDI

VSS

VDD

RxDO

OSC2

OSC1

CK32

ETC

MTC

TCO

FATC

18 PIN PLASTIC DIP/SOIC