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SYSTEM NETWORK MODULE (SNM)
13-2
13.2 SNM SETUP PROCEDURE
13.2.1 SNM SWITCH SETTINGS
See Figure 13-2 for 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.
13.2.2 AFSK COMMUNICATION ON THE MAIN
LINES
13.2.3 SNM JUMPER PLACEMENT
13.2.4 SNM BACKPLANE EXTERNAL CON-
TACTS
See the Backplane Section 23 for pinouts on the
shelf backplane and wire harness pinouts.
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.
Table 13-1 SNM SWITCH SETTINGS
Switch Open Sections Close Sections
AFSK Communication On The Main Line.
S1
S3
S4
S5
1
1
1
-
-
2
2
-
-
3
3
-
4
4
4
-
-
-
-
1
2
-
-
2
3
-
-
3
-
-
-
4
Table 13-2 SNM JUMPER PLACEMENT
JU Pin Description
J24 1 to 2*
2 to 3
Selects 27512 EPROM operation
Selects 27256 EPROM operation
J27 1 to 2
2 to 3*
Not used
Normal operation
P33 1 to 2
3 to 4
5 and 6
Jumpered
Jumpered
open
J36 1 only
1 to 2
2 to 3
Not used
-48V E-lead operation
-15V E-lead operation
J14
J15
J21
J22
Jumper pin 1 to 2 for high impedance ground path
for split 600 ohm inputs and outputs. Leave open if
no ground path desired.
* Indicates normal operation.
Table 13-3 SNM EXTERNAL CONNECTIONS
Backplane
P34 to P45
Description
Wire Harness
J1,3,5,7
pin 27
pin 28
pin 29
pin 30
pin 31
pin 32
Sec Rx +
Sec Rx -
EA lead
EB lead
Pri Rx Audio+
Pri Rx Audio-
pin 1
pin 2
pin 3
pin 4
pin 5
pin 6
RxS+
RxS-
EA
EB
RxA+
RxA-
J2,4,6,8
pin 59
pin 60
pin 61
pin 62
pin 63
pin 64
Sec Tx +
Sec Tx -
MA lead
MB lead
Pri Tx Audio+
Pri Tx Audio-
TxS+
TxS-
MA
MB
TxA+
TxA-
pin 1
pin 2
pin 3
pin 4
pin 5
pin 6