Verilink DIU 2130 (880-503297-001) Product Manual - Manual (Page 97)

DIU/DIM Details
Verilink 7-17
The associated DIUs also perform channel conditioning by sending
all-ones idle bytes to the connecting customer data equipment.
Each DIU also negates the CTS, DSR, and DCD signals to the data
equipment as previously described for the CSU T1 multiplexer
mode of operation.
In the opposite direction, the near-end CSU sends the incoming VF
on channels 1 through 12 from the channel bank to the network. It
also continues inserting normal DIU data into channels 13 through
24, and sends an RAI to the network if the network is ESF-framed.
The far-end CSU responds by sending the incoming VF from the
network to the channel bank via channels 1 through 12. It also
sends all-ones idle bytes on the drop-and-insert channels (13
through 24) to the channel bank for channel conditioning. The far-
end CSU also drops off the incoming data on channels 13 through
24 from the network to the DIUs. In addition, it continues sending
VF from the channel bank to the network on channels 1 through 12,
along with DIU data on the remaining channels. Each far-end DIU
also performs the channel conditioning operations previously
described for the CSU T1 multiplexer mode.
NOTE: If the CSU is programmed for SF framing, it neither
generates nor responds to a received RAI. Therefore, channel
conditioning will not occur at the far-end CSU and DIUs.
• LOF Detection from the Equipment
—Figure 7-20 shows LOF
processing when a CSU in the drop-and-insert mode detects an
LOF from the equipment and is programmed for ESF framing
on the network. If the drop-and-insert is toward the network
(Figure 7-20), the CSU continues inserting DIU data into
channels 13 through 24 toward the network. It also sends all-
ones idle bytes to the network on channels 1 through 12 from
the equipment for far-end DS-1 equipment channel
conditioning.
In the opposite direction, the CSU sends the VF on channels 1
through 12 of the incoming network signal to the channel
bank. It also inserts all-ones on channels 13 through 24 and
sends this data to the equipment. In addition, if the CSU
detects an LOF from the equipment, it sends an RAI to the
equipment. If the equipment uses SF framing, the RAI (all B2
bits = zeros) overwrites the data on all channels.