Instruction manual

Lines
Planning Form Instructions—Continued
10.
If installing more than one 100D Module, decide which Module, if any,
provides the primary synchronization.
■
If Module 1 provides clock synchronization, check "Primary" in the
first column (the factory setting).
■
If Module 2 (or Module 3) provides clock snychronization, check
"Primary" in the column that describes that 100D module.
■
If the synchronization source is other than through a 100D module
check "None".
If assigning backup synchronization:
■
Check "Secondary" in the column that describes the 100D module
providing secondary synchronization.
■
Check "Tertiary" in the column that describes the 100D module
providing tertiary backup.
11.
Under the "Source" subheading in each column:
■
Check "Loop" to retain the factory setting. The system uses the clock
of the far-end connection.
■
Check "Local" to change the setting. (Clock is free running).
12.
Under the "Activation" subheading in each column:
■
Check "Active" if loop clock synchronization is taking place.
■
Check "Not Active" if the clock is free-running.
Note: Normally, the primary synchronization source is set to "active" and
other modules are set to "not active".
Signaling Mode
Signaling is the process of communicating channel-state information (such as
dialing) from endpoint to endpoint. Two types of signaling can be used in T1
transmission: robbed-bit signaling (RBS) and common-channel signaling (CCS).
Note: The signaling mode setting does not apply to ISDN-PRI.
Robbed-Bit Signaling. RBS replaces ("robs") the Ieast significant bit of every
sixth frame of each DS0 channel with signaling information. (RBS is also
called in-band signaling, since signaling information is embedded in the
least significant bit of every sixth 8-bit word.)
RBS is appropriate for voice and voice-grade data, but facilities using RBS
cannot accurately transmit digital data because digital data uses high-speed
data rates such as 64 kbps. Therefore, the channel is limited to voice and
analog voice-band data applications.
Common-Channel Signaling. CCS is an ‘out-of-band’ signaling format that
places the signaling bits for channels 1 through 23 into the 8-bit word of the
24th channel. The 24th channel, therefore, cannot be used for voice or data
transmissions.
3-20 Line options