Demand test descriptions and error codes - Avaya Support

The DS1 converter complex can replace fiber links between two EIs and fiber links between an
PN’s EI and an SNI. Fiber links between two SNIs and fiber links between the and the Center
Stage Switch (CSS) cot be replaced by a DS1 converter complex.
On the TN574 DS1 converter circuit pack, one of the four DS1 facilities is used as the primary
facility (or packet facility), and it is the only facility that can carry packet traffic besides providing
circuit connections. The primary facility has 22 chels available for circuit and packet
connections. Other facilities each have 24 chels available for circuit connections. On the TN574
primary facility, chels 1 and 24 are not available for packet or for circuit connections. Chel 1 is
used for excess packets traffic to prevent packet overflow that might result from zero code
substitutions. Chel 24 is the DS1 control chel that carries control link data between the two DS1
converter circuit packs.
The primary facility on the TN1654 DS1 converter circuit pack is restricted to facility A or facility
B. The TN1654 provides fixed packet bandwidth of 192 kbps while the TN574 provides packet
bandwidth of up to 1408 kbps with a dynamic allocation mechanism that could change packet/
circuit use of individual chels. The first three 64-kbps chels on the primary facility of the TN1654
are reserved as the packet chels. The DS1 control chel will be Chel 24 in T1 mode and Chel 31
in E1 mode. In T1 format the TN1654 provides 24 circuit chels for use on non-primary facilities
and 20 circuit chels on the primary facility. E1 format provides 31 circuit chels for use on
non-primary facilities and 27 circuit chels on the primary facility.
When there are alarms on the packet facility, DS1 converter circuit pack firmware changes the
mapping of the DS1 chels to move the packet traffic to another facility. On TN574 DS1 converter
boards, the packet traffic will be moved to another “Digital Data Compatible” facility (as
indicated on the fiber link administration screen). On TN1654 DS1 converter boards, the packet
traffic will be moved to either facility A or B if available. This mapping is done to keep the packet
service operational at all times as the system control links are carried on these packet
connections. When packet traffic is moved to another facility, circuit connections on the new
facility are torn down and circuit connections on the old (faulty) facility are re-mapped to the new
packet facility.
After firmware initialization, facility A, the first facility, is chosen as the default primary facility for
both DS1 converter boards.
The TN574 DS1 converter has seven LEDs that provide an indication of the state of the DS1
converter circuit pack and the DS1 facilities. There is a yellow, a green, and a red LED under
software and/or firmware control. There are four Green LEDs under hardware control that
indicate, for each DS1 facility, whether a receive signal is present for the DS1 facility. From top
to bottom these green LEDs correspond to DS1 facilities A, B, C, and D respectively. If one of
the four green LED is on, it indicates a signal is present, but it does not imply that the signal is
using the correct framing format (ESF or D4) or line coding (ZCS or B8ZS). See section
DS1C-BD for the description of the red, the green, and the amber LEDs on the DS1 converter
circuit pack.
356 Maintenance Alarms for Communication Manager, Media Gateways and Servers