AIS Router AI2524 - Manual (Page 369)

Chapter 14: T1 Interface Configuration Steps
August 1997 Page 14-3
2524UM
To transmit packets without decreasing outgoing signal strength, typ
this in interface configuration mode:
service-module t1 lbo none
The ideal signal strength should be between -15 dB and -22 dB, which
is calculated by adding the phone company loss, cable length loss, and
line build out.
You may use this command in back-to-back configurations, but it is
not needed on most actual T1 lines.
Specify FT1/T1 Line-Code Type
To configure the line code for the FT1/T1 CSU/DSU module, type this
in interface configuration mode:
service-module t1 linecode {ami | b8zs}
Choose alternate mark inversion (AMI) or binary 8 zero substitution
(B8ZS).
Configuring B8ZS is a method of ensuring the T1s density require
ment on a T1 line by substituting intentional bipolar violations in bit
positions four and seven for a sequence of eight zero bits. When the
CSU/DSU is configured for AMI, you must guarantee the T1s density
requirement in your router configuration using the
service-mod-
ule t1 data-coding inverted command or the service-
module t1 timeslots speed 56 command.
In most cases, your T1 service provider determines which line-cod
type, either
ami or b8zs , is required for your T1 circuit.
Enable Remote Alarms
To generate remote alarms (yellow alarms) at the local CSU/DSU or
detect remote alarms sent from the remote CSU/DSU, type this in in-
terface configuration mode:
service-module t1 remote-alarm-enable
Remote alarms are transmitted by the CSU/DSU when it detects an
alarm condition, such as a red alarm (loss of signal) or blue alarm (un-
framed 1's). The receiving CSU/DSU then knows there is an error con-
dition on the line.
With D4 super frame configured, a remote alarm condition is transmit-
ted by setting the bit2 of each time slot to zero. For received user data
that has the bit 2 of each time slot set to zero, the CSU/DSU will inter-
pret the data as a remote alarm and interrupt data transmission, which
explains why remote alarms are disabled by default. With Extended