GE Digital Energy L30, Инструкция по эксплуатации, Страница: 86 / 644

3-28 L30 Line Current Differential System GE Multilin
3.3 PILOT CHANNEL COMMUNICATIONS 3 HARDWARE
3
7. Re-insert the G.703 module. Take care to ensure that the correct module type is inserted into the correct slot position.
The ejector/inserter clips located at the top and at the bottom of each module must be in the disengaged position as
the module is smoothly inserted into the slot. Once the clips have cleared the raised edge of the chassis, engage the
clips simultaneously. When the clips have locked into position, the module is fully inserted.
Figure 3–31: G.703 TIMING SELECTION SWITCH SETTING
c) G.703 OCTET TIMING
If octet timing is enabled (ON), this 8 kHz signal is asserted during the violation of bit 8 (LSB) necessary for connecting to
higher order systems. When L30s are connected back-to-back, octet timing is disabled (OFF).
d) G.703 TIMING MODES
There are two timing modes for the G.703 module: internal timing mode and loop timing mode (default).
• Internal Timing Mode: The system clock is generated internally. Therefore, the G.703 timing selection should be in
the internal timing mode for back-to-back (UR-to-UR) connections. For back-to-back connections, set for octet timing
(S1 = OFF) and timing mode to internal timing (S5 = ON and S6 = OFF).
• Loop Timing Mode: The system clock is derived from the received line signal. Therefore, the G.703 timing selection
should be in loop timing mode for connections to higher order systems. For connection to a higher order system (UR-
to-multiplexer, factory defaults), set to octet timing (S1 = ON) and set timing mode to loop timing (S5 = OFF and S6 =
OFF).
Table 3–4: G.703 TIMING SELECTIONS
SWITCHES FUNCTION
S1 OFF

octet timing disabled
ON

octet timing 8 kHz
S5 and S6 S5 = OFF and S6 = OFF

loop timing mode
S5 = ON and S6 = OFF

internal timing mode
S5 = OFF and S6 = ON

minimum remote loopback mode
S5 = ON and S6 = ON

dual loopback mode