SYSTEM NETWORK MODULE (SNM)

13.2 SNM SETUP PROCEDURE

13.2.1 SNM SWITCH SETTINGS

See Figure 13-2for Alignment Points Diagram.

Command and Control Communication

The command and control communication is by blank and burst signaling using Audio Frequency Shift Keyed data on the Main audio lines.

13.2.2AFSK COMMUNICATION ON THE MAIN LINES

Table 13-1 SNM SWITCH SETTINGS

Switch

 

Open Sections

 

Close Sections

 

 

 

AFSK

Communication On

The Main Line.

 

 

 

 

 

 

 

 

 

S1

1

-

-

4

-

2

3

-

S3

1

2

3

4

-

-

-

-

S4

1

2

3

4

-

-

-

-

S5

-

-

-

-

1

2

3

4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

13.2.3 SNM JUMPER PLACEMENT

Table 13-2 SNM 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

Jumpered

 

3 to 4

Jumpered

 

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.

13.2.4SNM BACKPLANE EXTERNAL CON- TACTS

See the Backplane Section 23 for pinouts on the shelf backplane and wire harness pinouts.

Table 13-3 SNM EXTERNAL CONNECTIONS

Backplane

Description

Wire Harness

P34 to P45

 

J1,3,5,7

 

 

 

 

 

 

pin 27

Sec Rx +

pin 1

RxS+

pin 28

Sec Rx -

pin 2

RxS-

pin 29

EA lead

pin 3

EA

pin 30

EB lead

pin 4

EB

pin 31

Pri Rx Audio+

pin 5

RxA+

pin 32

Pri Rx Audio-

pin 6

RxA-

 

 

 

J2,4,6,8

 

 

 

 

pin 59

Sec Tx +

TxS+

pin 1

pin 60

Sec Tx -

TxS-

pin 2

pin 61

MA lead

MA

pin 3

pin 62

MB lead

MB

pin 4

pin 63

Pri Tx Audio+

TxA+

pin 5

pin 64

Pri Tx Audio-

TxA-

pin 6

13.3 SNM ALIGNMENT SPECIFICATIONS

13.3.1 PRE-ALIGNMENT

The SNM is pre-aligned with the Basic Board Module alignment procedures; refer to Section 7.3.

13.3.2 SNM ALIGNMENT PROCEDURE

Connections to the SNM may take several forms:

1.Direct Connection

2.Leased Lines

3.Microwave Link

4.T1 Channel Bank Interfaces

This ancillary equipment requires certain input and output levels for proper operation. The module should be adjusted accordingly.

13-2