
SYSTEM NETWORK MODULE (SNM)
13.2.1 SNM SWITCH SETTINGS
See Figure
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
TableSwitch |
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AFSK | Communication On | The Main Line. | ||||||
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S1 | 1 | - | - | 4 | - | 2 | 3 | - |
S3 | 1 | 2 | 3 | 4 | - | - | - | - |
S4 | 1 | 2 | 3 | 4 | - | - | - | - |
S5 | - | - | - | - | 1 | 2 | 3 | 4 |
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13.2.3 SNM JUMPER PLACEMENT
TableJU | Pin | Description |
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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 | |
| 2 to 3 | |
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 |
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* 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.
TableBackplane | Description | Wire Harness | |
P34 to P45 |
| J1,3,5,7 | |
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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- |
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| J2,4,6,8 |
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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 |
13.3.1
The SNM is
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.