AT&T MERLIN LEGEND Communications System PBX System Planning Manual page 74

Trunks
See "Signaling Mode" in this chapter.
Frame Format
Planning Form Instructions
On PBX System Form 2c, System Number - Trunk Jacks, in the "Jack
Type" column:
1.
Find all trunks listed as "PRI."
Write the king of service connected to each channel in the "Trunk
Type" column.
Note: You cannot use the 24th channel for services.
Write "unequipped" in the "Trunk Type" column for any channel not
used at this time.
2 .
Find all trunks listed as "T1-Tie" that do not show "unequipped" in the
"Trunk Type" column.
Write the kind of service connected to each channel in the "Trunk
Type" column.
Note: If the signaling type is common-channel, you cannot use the
24th channel and program the module for tie-trunk emulation.
On page 1 of PBX System Form 3c, Outside Trunks - DS1 Facility (100D
Module), for each 100D module in the system:
3 .
Write the number of the control unit slot (in the "Slot No." blank) that
contains the module. (Refer to the "Control Unit Diagram" on Form 1.)
If more than one 100D module is used, complete the first column,
"Module 1," to show the options assigned to the 100D module in the
lowest number control unit slot. Use the second column for the second
lowest number slot and the last column for the high number slot.
4 .
Show the service connected to each 100D module, under the "Type of
Service" heading.
Check "T1" (the factory-setting) if the module is used for emulated
trunks and/or services such as Megacom 800 with DNIS.
Check "ISDN-PRI" if the module is used exclusively for services such
as Accunet Switched Digital Service.
To identify the DSO channels, the DS1 signal is segmented
bits, called frames. A frame consists of
channel) plus a framing bit at the beginning of each frame: 24 words x 8 bits =
192 bits. Thus, a framing bit appears in every 193rd bit position of the
1.544-Mbps DS1 signal.
Frames repeat at a rate of 8000 per second, with each frame repeating DSO
channels 1 through 24 sequentially.
blocks of 193
into
24 eight-bit words (one for each
Trunk Options 3-19