Loop Detector; Ani And Coin Presence; Ringing - Nortel DMS-100 Series Maintenance Manual

9-54 Trouble isolation and correction

Loop detector

The loop detector test checks the capability of the line circuit to detect
off-hook or on-hook conditions. The loop detector test runs as part of test
setup. The SMS sends an A- and B-bit pattern that causes the RCS to apply
an absorb termination. This termination simulates an off-hook at the RCS.
The RCS must detect this termination as an off-hook. The RCS must send
the SMS the A- and B-bit pattern associated with off-hook. Idle A- and
B-bits must be sent before the RCS detects termination as off-hook.
To remove the termination, the SMS sends the RCS an on-hook message in
the M-field of the DDL. The RCS must detect removal of the termination as
a simulated on-hook. The RCS must send the SMS the on-hook A- and
B-bit pattern associated with on-hook subscriber lines.

ANI and coin presence

The ANI test and the coin presence test check the ability of the line card to
simulate tip party off-hook and coin presence. The ANI test detects the
termination that simulates tip party off-hook or coin presence. Then the
ANI returns an A- and B-bit signaling pattern to the SMS. This pattern
indicates tip party off-hook or coin presence.
The SMS sends A- and B-bit patterns associated with different polarities of
ringing on multi-party lines. These patterns cause the RCS to setup
terminations with and without NTPG/PTPG. For example, the A- and B-bit
pattern associated with negative superimposed ringing on the tip –T causes
the setup of a reflect-NTPG termination.
When the termination is a reflect-NTPG or absorb-NTPG, the ANI test
indicates a tip party off-hook. Other terminations indicate ring party
off-hook. A reflect-NTPG or absorb-NTPG termination simulates coin
presence. Other terminations simulate lack of coin presence. The test fails
if the SMS does not receive a correct reply.

Ringing

The ringing test checks the ability of an RCS line card to ring a subscriber
line. The SMS sends a specified A- and B-bit pattern for –R ringing and
other A- and B-bit patterns for +R, –T, and +T ringing on multi-party lines.
The SMS can send the RCS an A- and B-bit pattern that requests the RCS to
ring a subscriber line. When this event occurs, the RCS sets up a specified
termination. This termination simulates a subscriber off-hook. This
termination causes RCS to return an off-hook A- and B-bit pattern to the
SMS.
297-8231-550 Standard 09.01 August 1998