GE Multilin L90 Line Current Differential System 3-413 HARDWARE 3.3 PILOT CHANNEL COMMUNICATIONS3For the looped timing mode, the system clock is derived from the received line signal. Therefore, the timing selectionshould be in loop timing mode for connections to higher order systems.The C37.94SM communications module cover removal procedure is as follows:1. With power to the relay off, remove the C37.94SM module (modules 2A or 2B):Pull the ejector/inserter clips located at the top and at the bottom of each module simultaneously in order to release themodule for removal. Record the original location of the module to help ensure that the same or replacement module isinserted into the correct slot.2. Remove the module cover screw.3. Remove the top cover by sliding it towards the rear and then lift it upwards.4. Set the timing selection switches (channel 1, channel 2) to the desired timing modes (see description above).5. Replace the top cover and the cover screw.6. Re-insert the C37.94SM module. Take care to ensure that the correct module type is inserted into the correct slotposition. The ejector/inserter clips located at the top and at the bottom of each module must be in the disengaged posi-tion 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 will be fully inserted.Figure 3–44: C37.94SM TIMING SELECTION SWITCH SETTING
