Dms Exchange - Lt1 Flag; Programming Required For E1 Pri (Isdn) - Mitel 3000 Installation And Maintenance Manual

Mitel 3000
Installation & Maintenance Manual
T1 (RBS) States
The signaling states On-hook / Off-hook for both Transmit and Receive direction are shown for every T1
channel. The current states are presented when the panel is opened, and are refreshed every 3 seconds thereafter.
D-Channel signaling
The diagnostics application shows the D-Channel activity in real time. An interpreter is also provided to display
the message information in English.
DMS Exchange – LT1 Flag
It is recommended that before troubleshooting any PRI issue that the Central Office EQUIPMENT type be
confirmed, not the ISDN switch type or protocol, the Equipment type. If the equipment providing the PRI circuit
is DMS then you need to confirm that the LT1 flag is set to YES. The DMS is the only CO Equipment that has
this LT1 flag.
The DMS Central Office Exchange equipment manufactured by Nortel provides a special or proprietary PRI
setting for their own telephone business systems. By default, this setting in the DMS Central Office is enabled for
the PRI circuits provided by the DMS exchange. The special setting in the DMS switch is called the LT1 flag.
The LT1 flag is located under the Trunk Sub Group in the DMS programming. When installing a NON Nortel
product with PRI behind a DMS Central Office this LT1 flag must be set to Yes or the PRI circuit will have
issues (see list below).
If the DMS Central Office has the LT1 flag set to NO instead of YES the Mitel system will have the following
issues:
The system will allow incoming calls but denies access for outgoing calls. The B-Channels are busy and not
releasing for long periods of time.
SUMMARY:
If the Central Office providing the PRI circuit is a DMS (Nortel) exchange the LT1 flag under the trunk sub
group must be set to YES. This setting is in the DMS equipment not in the Mitel system. This issue with the LT1
flag only applies to the DMS Central Office Equipment (Nortel Only). This LT1 flag does not exist with any
other Central Office Exchange manufacturer (Siemens, Lucent, Copper Com etc).
The LT1 flag in the Nortel DMS exchange equipment provides a special interface for Nortel telephone equipment
when using PRI when the LT1 flag is set to NO. For the Mitel product it must be set to YES.
The DMS-100 setting in the Mitel system is Nortel Custom. Some Nortel Test technicians call Nortel Custom,
National ISDN 1. DMS-100 is the Nortel Specifications for Nortel Custom protocol so called National ISDN 1.
All DMS Central Office equipment (DMS 100, 200, 250 and 500) are all the same concerning the LT1 flag.
If the Nortel DMS Central Office is providing Nortel Custom (sometimes called National ISDN 1) or National
ISDN 2 protocol (ISDN Switch Type) this flag LT1 flag must be set to YES.
Maintenance procedures
Faults can be rectified on-site by replacing faulty modules or PCBs (Printed Circuit Boards).

Programming required for E1 PRI (ISDN)

The default programming of the T1/E1 PRI Module is that it is set as T1 (RBS). The programming must be
changed to provide an E1 PRI circuit. E1 PRI This programming is described on page 109.
Changing from T1 (RBS) to PRI (ISDN) and vice versa only takes effect when the switch is
reset. If you go on hook at the programming position after changing the setting, the switch will
automatically reset
Trunk type has to be programmed. T1 or E1 needs to be selected from the System programming.
See page
46