DISPATCH CHANNEL MODULE (DCM)

SECTION 10 DISPATCH CHANNEL MODULE (DCM)
10.1 DESCRIPTION

Refer to 3000 Series Switch Service Information manual, Part No. 001-3139-102, for the component layout, parts list and schematic. Refer to Figure 7-1for the Basic Board block diagram. The Dispatch Channel Module (DCM) connects the Switch to a Conventional Repeater. Each repeater has a DCM that controls the repeater through logic signaling.

10.1.1 REPEATER SIGNALING

The DCM exchanges control information with the CRM via Audio Frequency Shift Keying (AFSK) data in a blank and burst mode on the voice audio path.

10.1.2 REPEATER CONTROL

The DCM monitors and controls the repeater transmit, receives confirmation of all requests made to the repeater and sends information the repeater received.

10.2 DCM SETUP PROCEDURE

10.2.1 DCM SWITCH SETTINGS

Refer to Figure 10-1for the Alignment Points Diagram.

Command and Control Communication

The command and control communication to the Conventional Repeater Module (CRM) is by blank and burst mode of Audio Frequency Shift Keyed data on the Main audio lines.

10.2.2AFSK COMMUNICATION ON THE MAIN LINES

Refer to Table 10-1for switch settings.

Table 10-1 DCM SWITCH SETTINGS

Switch

Open Sections

 

Close Sections

 

 

 

 

 

 

 

 

 

 

S1

1

-

-

4

-

2

3

-

S3

1

2

3

4

-

-

-

-

S4

1

2

3

4

-

-

-

-

S5

-

-

-

-

1

2

3

4

10.1.3 VOICE CONNECTION

The DCM provides a 4-Wire 600 ohm balanced voice connection to the repeater, converts audio to and from Pulse Code Modulation (PCM), transmits and receives on the PCM buses, and controls voice audio gating to and from the repeater.

10.1.4 INTERNAL COMMUNICATION

The DCM uses the Intra-Terminal Data Bus (IDB) to communicate to other modules and send messages to and receive messages from the Call Processor that controls its actions.

The DCM monitors the CSB to determine if a CIM is active with the appropriate group.

10.2.3 DCM JUMPER PLACEMENT

Table 10-2 DCM JUMPER PLACEMENT

JU

Pin

Description

 

 

 

J24

1 to 2*

Selects 27512 EPROM operation

 

2 to 3

Selects 27256 EPROM operation

J27

1 to 2

Not used

 

2 to 3*

Normal operation

P33

1 to 2

open

 

3 to 4

open

 

5 and 6

open

J36

1 only

Not used

 

1 to 2

-48V E-lead operation

 

2 to 3

-15V E-lead operation

J14

Jumper pin 1 to 2 for high impedance ground path

J15

for split 600 ohm inputs and outputs. Leave open if

J21

no ground path desired.

J22

 

 

* Indicates normal operation.

10-1