GE UR Series Instruction Manual page 66

3.3 L90 CHANNEL COMMUNICATION 3 HARDWARE
d) TIMING MODES (S5 & S6)
Internal Timing Mode:
System clock generated internally; therefore, the G.703 timing selection should be in the Internal Timing Mode for back to
back connections.
Figure 3–27: BACK TO BACK CONNECTION
For Back to Back Connections: Octet Timing (S1 = OFF); Timing Mode = Internal Timing (S5 = ON & S6 = OFF)
3
Loop Timing Mode:
System clock derived from the received line signal; therefore, the G.703 timing selection should be in Loop Timing Mode for
connections to higher order systems.
Figure 3–28: CONNECTION TO HIGHER ORDER SYSTEM
For connection to a higher order system (factory defaults): Octet Timing (S1 = ON);
Timing Mode = Loop Timing (S5 = OFF & S6 = OFF)
e) TEST MODES (S5 & S6)
Minimum Remote Loopback Mode:
In Minimum Remote Loopback mode, the multiplexer is enabled to return the data from the external interface without any
processing to assist in diagnosing G.703 Line Side problems irrespective of clock rate. Data enters from the G.703 inputs,
passes through the data stabilization latch which also restores the proper signal polarity, passes through the multiplexer
and then returns to the transmitter. The Differential Received Data is processed and passed to the G.703 Transmitter mod-
ule after which point the data is discarded. The G.703 Receiver module is fully functional and continues to process data
and passes it to the Differential Manchester Transmitter module. Since timing is returned as it is received, the timing source
is expected to be from the G.703 line side of the interface.
Dual Loopback Mode:
In Dual Loopback Mode, the multiplexers are active and the functions of the circuit are divided into two with each Receiver/
Transmitter pair linked together to deconstruct and then reconstruct their respective signals. Differential Manchester data
enters the Differential Manchester Receiver module and then is returned to the Differential Manchester Transmitter module.
Likewise, G.703 data enters the G.703 Receiver module and is passed through to the G.703 Transmitter module to be
3-24 L90 Line Differential Relay GE Power Management