51
APPENDIX D: G.703 Rear Card Module
Table D-1. Operation mode.
S2
Setting
Off
Clear Channel Mode
On
Octet Timing Mode
Switch S3: Timing Mode
The setting of Switch S3 determines the source of the system timing. The system
timing may be provided by:
1. the G.703 network, or
2. the local function card or remote baseband line driver/CSU/DSU (either a
rackmountable function card or standalone unit).
Set Switch S3 to Network timing when only one of the two connected baseband
line drivers or CSU/DSUs employ a 64 k/G.703 interface card (the other line
driver connects to a V.35, EIA-232, etc. device).
Set Switch S3 to Modem timing when both of the connected baseband line drivers
or CSU/DSUs employ a 64 k/G.703 interface card. In this application, one G.703
interface card must be set to Modem timing, and the other must be set to Network
timing.
Switches S4 and S5: Reserved for future use
Switches S4 and S5 are reserved for future use and should remain in the Off
position.
