5.3 LOOPBACK TEST (LAL)
The Model 2703 is equipped with a Local Analog Loopback (LAL) mode to assist in evaluating the operation of the local Model 2703. Any data sent to the local Model 2703 in this test mode will be echoed (returned) back to the user device. For example, characters typed on the keyboard of a terminal will appear on the terminal screen. To per- form a LAL test, follow these steps:
A.Activate LAL by moving the front panel toggle switch UP and holding it in the “Loopback” mode. The “Loop” LED should glow. Once LAL is activated, the Model 2703 transmit output is connected to its own receiver.
NOTE: The front panel switch is spring loaded, so it will return to “Normal” operating mode when pressure is released. To put the Model 2703 in continual loopback mode, for the purpose of performing a BER test, move DIP switch
B.Verify that the data terminal equipment is operating properly and can be used for a test. If a fault is indicated, call a tech- nician or replace the unit.
C.Perform a BER (bit error rate) test on each unit. If the BER test equipment indicates no faults, but the data terminal indi- cates a fault, follow the manufacturer’s checkout procedures for the data terminal. Also, check the interface cable between the terminal and the Model 2703.
APPENDIX A
PATTON MODEL 2703 SPECIFICATIONS
Network Interface: | G.703 |
Network Rate: | 2.048 Mbps |
Network Connectors: | Two BNC (75 Ohm) and one |
| modular |
| Ohm) |
Terminal Interface: | EIA |
| V.35 on |
Terminal Rate: | 2.048 Mbps; |
| 1.024 Mbps, 512 kbps, 256 kbps |
Diagnostics: | Loopback Test |
Indicators: | LEDs for power, network, master |
| clock and loopback test |
Clocking: | Internal or network (receive |
| loop) |
Receiver Sensitivity: | |
Power: | 115/230 VAC (switch selectable), |
| 50/60 Hz; |
| (universal input option); 48 VDC |
Temperature Range: | (option) |
Altitude: | |
Humidity: | 5 to 95% |
Dimensions: | 7.3” x 6.6” x 1.62” (185mm x |
Weight: | 168mm x 41mm) |
2.02 lbs. |
15 | 16 |
