2-175

Preliminary Information

MH88622

17

NC

No Connection. This pin should not be connected.

18

NC

No Connection. This pin should not be connected.

19

RF1

Ringing Frequency Node 1 (Input). A capacitor is connected between RF1 & RF2 and

determines the frequency of the ringing generator.

20

RF2

Ringing Frequency Node 2 (Input). Two capacitors are connected between RF1& RF2

and from RF2 to AGND. This determines the frequency of the ringing generator.

21

RGV

Ringing Gain Voltage. Connects to RG1 through a resistor to reduce the output ringing

voltage. When left open circuit output ringing voltage is 90Vrms.

22

RG1

Ringing Gain Node 1. Connects to RGV through a resistor to reduce the output ringing

voltage. When left open circuit output ringing voltage is 90Vrms.

23

NC

No Connection. This pin should not be connected.

24

NC

No Connection. This pin should not be connected.

25

RC2

Ringing Control (Input). A logic level applied to this pin enables ringing to be applied

across Tip and Ring of subscriber 2.

26

LR2

Line Reversal. A logic 1 applied to LR2 will reverse the “Tip” and “Ring” to subscriber 2.

This pin has an internal pull down.

27

VDD

Positive Supply Voltage. +5Vdc. This pin should be connected to pin 14 of the hybrid on

the PCB.

28

GND

Ground. Return path for VDD, VEE, VBat & DCRI. This pin should be connected to pins 5,

13 & 36 of the hybrid on the pcb.

29

VEE

the PCB.

30

VX2

Transmit (Output). 4-Wire GND referenced audio input for subscriber 2.

31

LCS2

Loop Current Set 2. Logic 1 gives ILoop = 40mA, Logic 0 gives ILoop = 25mA.

32

SHK2

Off Hook Indication (Output). A logic high output indicates when subscriber 2 equipment

has gone off hook.

33

VR2

Receive (Input). 4-Wire GND referenced audio input for subscriber 2.

34

ESE2

External Signal Enable (Input). The external signal to subscriber 2 is controlled by a logic

level applied to this pin.

35

ESI2

External Signal Input. A continuous signal should be applied to this pin which will be

switched to “Tip” and “Ring” of subscriber 2.

36

GND

Ground. This pin should be tied to pins 5, 13 & 28 on the PCB.

37

DCRI

DC Ringing Voltage Input. A continuous 120Vdc is applied to this input to achieve 90

Vrms ringing. This should be connected to pin 4 of the hybrid on the PCB.

38

VBAT

Battery Voltage. Typically -48V dc is applied to this pin. This should be connected to pin 3

of the hybrid on the PCB.

39

RING2

Ring Lead. Connects to the “Ring” lead of subscriber line 2.

40

TIP2

Tip Lead. Connects to the “Tip” lead of subscriber line 2.

Pin Description (Continued)

Pin #

Name

Description