2-54

MH88510/11

Preliminary Information

Figure 2 - Pin Connections

Pin Description

Pin #

Name

Description

1TIP

Tip Lead. Connects to the “Tip” lead (A-wire) of the telephone line.

2VDD

Positive Power Supply Voltage. Normally +5V. This provides current for both internal

circuitry as well as the loop. Not internally connected to pin 12.

3

RING

Ring Lead. Connects to the “Ring” lead (B-wire) of the telephone line.

4RF

Ring Feed. Connect to the Ring Relay contact. See Figure 5.

5

TF

Leave open circuit

6

VBAT

Battery Voltage Supply. Normally -24V or -48V. Not internally connected to pin 14.

7AGND

Analog Ground. Supply and battery ground. Internally connected to pin 13. For

optimum performance connect pin 7 to pin 13.

Negative Power Supply Voltage. Normally -5V.

9LED

LED Drive (Output). Drives an LED directly. A logic low indicates an off-hook condition.

10

SHK

Switch Hook Detect (Output). A logic low indicates an off-hook condition.

11

IC

Internal Connection. This pin is connected internally

12

Positive Power Supply Voltage. Normally +5V. This provides current for both internal

circuitry as well as the loop.

13

AGND

Analog Ground. Supply and battery ground. Internally connected to pin 13. For

optimum performance connect pin 13 to pin 7.

14

Battery Voltage Supply. Normally -24V or -48V. Not internally connected to pin 6.

15

MUTE

MUTE (Input). A logic low will mute signals coming from Tip-Ring to the JUNC.

16

JUNC

Receive/transmit audio speech path. (Referenced to 0V GND).

17

RRD

Ring Relay Drive (Output). Connects to the ring relay coil. A logic low activates the

relay.

18

RGND

Relay Ground. Return path for relay supply votlage. Normally connected to AGND.

19

RRC

Ring Relay Control (Input). A logic high activates the Ring Relay Drive (RRD) outputs.

20

VRLY

Relay Positive Supply Voltage. Normally +5V. Connects to the relay coil and the relay

supply voltage. An internal clamp diode from VRLY to RGND is provided.

TIP

VDD

RING

TF

VBAT

AGND

VEE

LED

SHK

IC

VDD

AGND

VBAT

MUTE

JUNCTOR

RRD

RF

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20