Nortel DMS-100 Series Maintenance Manual page 90

1-74 Maintenance overview
Protection link configuration
Protection switches are initiated:
The FELP command enables a continuous loopback on all 24 DS-1 channels
of a specified link.
When a protection switch occurs, calls in the talking state are maintained.
For POTS and coin lines, calls in the ringing state are also maintained. The
protection line carries voice and signaling information. If the A-link is
protection switched (or C-link in Mode II), the protection line carries system
control information.
This section calls a protection line a protection link. This section calls a
DS-1 link that normally works a primary link.
The SMS is put into service. Protection switching is automatically enabled
for each primary link of an RCS equipped with a protection link. If a
protection link is added to an RCS, all primary lines that connect to that
RCS are enabled for protection switching.
297-8231-550 Standard 09.01 August 1998
RCS
Protection link
automatically by the RCS or SMS
manually by operating company personnel who use the CARRIER level
PROTSW command
during execution of the FELP command
Network
SMS
RCS
Unprotected RCS
RCS