DEFINITY Enterprise Communications Server Release 8.2
Upgrades and Additions for R8r
555-233-115 Issue 1
April 2000
Fiber Link Administration
A-14Administer Fiber Links
A
■Line Coding — Enter the line coding format, ami-zcs (d efault), or
ami-basic, b8zs, or hdb3 in the A, B, C, and D columns und er the DS1
Converter Facilities heading for eac h DS1 facility.
When ami-zcs line coding is used, all-zero bytes are prevented from b eing
transmitted on the DS1 facility bec ause a 1 is arbitrarily written into the
second position of ea ch byte. Thus, if no measures are taken to prevent it,
ami-zcs line coding results in data corruption. The DS1CONV circuit pack
protects the pack et facility (one of up to four facilities d ynamically
allocated by the DS1CONV circu it pack) from corruption throug h a special
escape mechanism.
When b8zs line coding is used, it maintains DS1 facility’s ones-density
requirements by encod ing a zero data byte into a sp ecific unique patter n
of bipolar violations on the DS1 line. The opp osite end recognizes this
pattern and replac es it with a zero data byte when the da ta is recovered at
the receiving end.
NOTE:
Note that although the esf framing mod e and b8zs line codin g are
the preferable modes of op eration, you should confirm that th e DS1
facilities support them before selecting this line c oding.
■Framing Mode — Enter the framing format, esf (default) or d4, in the A,
B, C, and D columns under the DS1 Converter Facilities heading for each
DS1 facility.
NOTE:
The D4 format is supported b y the Converter circuit pac ks, but
because of probl ems inherent with this format (specifically, inability
to frame on a bit stream that contains d ata that emulates the D4
framing pattern), its use is d iscouraged.
■DS1CONV-1 Line Compensation — Enter the line compensation (1 to 5)
in the A, B, C, and D columns und er the DS1 Converter Facilities heading
for each DS1 facility connected to ENDPOINT-1 (see Table 6-15).
The DS1 line signal is pre-equalized at the tran smitter so that DS1 line
pulses are the correct amp litude and shape when they reach the Netwo rk
Interface. The amount of equalization nec essary is determined b y the
distance to the Network Interfac e (when the endpoint supp lies a DSX-1
interface) and also by the type of wiring used to conn ect to the Network
Interface. The types of wiring allowed are 22 gauge ABAM (shielded
twisted pair) cab le, 24 gauge Premises Distribution System (PDS) wiring,
and 26 gauge PDS wiring.