RFL Electronics RFL 9300 - Verification of End-To-End Communications

RFL 9300 RFL Electronics Inc.
October 20, 2004 8 - 18 (973) 334-3100
8.3 VERIFICATION OF END-TO-END COMMUNICATIONS
Five different procedures are provided for verifying end-to-end communications: one for modem versions of the
RFL 9300, one for direct digital versions, one for fiber optic versions, one for short haul fiber versions, and one
for G.703 versions. Use the proper procedure for your RFL 9300:
Version Paragraph
Modem 8.3.1
Direct Digital 8.3.2
Fiber Optic 8.3.3
Short Haul Fiber 8.3.4
G.703 8.3.5
8.3.1 MODEM COMMUNICATIONS
The following procedure verifies end-to-end communications for RFL 9300 relays equipped with modems. A
multimeter or VOM will be required to perform this procedure.
1. Make sure the phone line being used (either dedicated metallic or multiplexed) is rated SPO
Class A (Service Performance Objective – Class A).
Using an SPO Class A line will guarantee communications before, during, and af-
ter a fault condition. For more information on SPO classifications, see Appendix
B of this manual.
2. Make sure the connections to the phone line have been properly made.
Connections should be as follows:
Transmit TB10-1 to TB10-2
Receive TB10-3 to TB10-4
3. Set the multimeter or VOM for ac voltage measurements.
4. Check the transmit output level by connecting the multimeter leads across rear-panel terminals
TB10-1 and TB10-2.
For telephone circuits, the meter indication should be about 0 dBm (0.8 volts for
600 ohm termination). For microwave or UHF radio, the desired level may be dif-
ferent, depending upon the communications equipment being used. Adjust the
TX ADJ potentiometer on the front of the 93B MO module for the desired output
level. The 93B MO module's output range is –20 dBm (TX ADJ fully counter
clockwise) to +8 dBm (TX ADJ fully clockwise).
5. Check the receive input level by connecting the multimeter leads across rear-panel terminals
TB10-3 and TB10-4.
The 93B MO's AGC circuit enables it to receive signals from -39 dBm to 0 dBm;
most telephone circuits have a nominal receive level of -16 dBm. If the meter in-
dication is much high or lower than this, it must be re-adjusted. (Refer to the
documentation supplied with the telephone or radio receiver equipment for the
level adjustment procedure.)
If desired, jumper J1 on the 93B MO module can be placed in Position B (TEST).
This will attenuate the receive input signal by about 3 dB, which may be enough
to bring the received signal into the range of the AGC circuit.