CTC Union TRM01, Руководство пользователя

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Chapter 5. Troubleshooting
28
TRM-01 APR 2000
5.3 Configuration
When physical connections have been confirmed, start looking for
configuration problems. Confirm that the proper line code is being used. The
FT1 Cards all support AMI and B8ZS line codes. In almost all instances, the
line code will be B8ZS. Confirm settings.
Framing errors can result if setting errors are made. Confirm the mode,
whether which framed-format. If both sides of the T1 link are using different
framing, there will be alarm indications.
Data errors may result if the timeslot assignments in fractional mode do
not match. Check the settings carefully. For reduced monthly charges, a
customer may only request a fraction of the T1 bandwidth. In this instance, an
ISP may provide a fraction of the full 1.544Mbps bandwidth to a customer by
utilizing Fractional T1. If only 512Kbps is requested, only eight (8) timeslots
are required to carry the data payload. Carefully check the settings at the central
site and confirm that the same eight timeslots are active on each end of the link.
Configuration check list:
T1 Line Code : Under most circumstances, line code should be set to B8ZS. Confirm
settings on both sides of the T1 link. (Sw6-4)
Frame Mode : Confirm switch settings for unframed or framed. Both sides of T1 link
must match. (Sw6-5, Sw2~Sw4 all off is unframed mode)
Timeslot settings : Double check same active timeslots on each side of link. (Sw2, Sw3,
Sw4)
Cascade : If not cascading, ensure this setting is off. (Sw7-4)
Data channel rate : May be set for 56 or 64Kbps. (Sw6-8)
DTE/DCE : The FT1 Card's data port is DCE. Connect to DTE equipment or custom
make the appropriate "null" cable.
System timing : In point-to-point applications, one unit must provide clock, whether
from internal or from the data port. The other unit must be set to recovery. For network
connections, both units are usually set to recovery, as the network provides the timing
source.