ADCP-50-304 • Issue 19 • June 1999 • Section 2: Functional Description

4 A/B SWITCHING MODULE (PSM-03)

This module provides A/B switching only. A simplified circuit diagram of this module is shown in Figure 2-8.

The A/B switch activates the A/B relays. The A/B relays complete the channel between the DCE and either DTE-A or DTE-B. The relays also switch in the interlock jumper. Interlocking from the control module protects the user from accidentally switching common backup equipment onto two or more different data lines. The three classes of interlock groups available are:

1.Global Interlock: Groups 1 and 2 are global and may be extended to all chassis in a system, using a 20-pin interchassis interlock cable. With this grouping, all modules having a jumper placed on group 1 make up one group, and all modules with a jumper on group 2 make up the other group. Interchassis interlock cables must be installed between chassis. Each module interlock group may have no more than one jumper installed at one time.

2.Horizontal Interlock: Groups 3 and 4 are horizontal and they include only modules in the individual chassis. With this grouping, all modules having a jumper placed on group 3 make up one group and all modules with a jumper on group 4 make up the other group. These groupings do not extend out of the chassis and are not affected by the interchassis interlock cable. Each module interlock group jumper block may have no more than one jumper installed at a time.

3.Vertical Interlock: The vertical interlock jumper position is labeled V. Placing a jumper in this position interlocks all modules in the same slot location in other chassis having a jumper installed on the came V position. Interchassis interlock cables must be installed between chassis. The interchassis interlock cable is a 20 position ribbon cable (4WC-03) with a 20-pin connector for each chassis. Each module interlock group jumper block may have no more than one jumper installed at a time.

TOGGLE

A

A/B

A/B

 

 

SWITCH

B

SWITCH

REPLAYS

 

 

LOGIC

 

 

 

 

 

 

 

 

 

 

 

A/B

 

 

 

 

 

INTERLOCK

 

 

A

 

 

JUMPER

 

INDICATORS

 

 

GROUP 1

 

B

 

 

 

 

 

 

 

 

 

 

 

A/B

2

 

 

 

 

 

 

 

 

 

REPLAYS

3

BACKPLANE

 

 

 

 

4

 

 

 

 

ALARM

V

 

 

 

 

 

 

 

 

 

 

 

1612-A

Figure 2-7. Patch Module with A/B Switching Detailed Circuit Diagram

Page 2-12

© 1999, ADC Telecommunications, Inc.