Nortel Circuit Card 311 Reference page 149

Figure 25
Traditional OPS application configuration
Copyright © 2003-2008, Nortel Networks
.
Note 1: OPS service should not be confused with off-premise extension
(OPS) service. OPS service is the provision of an extension to a
main subscriber loop bridged onto the loop at the serving CO or PBX.
Additionally, OPS as used to denote off-premise extension service
should not be confused with the OPS class-of-service assigned in the
Single-line Telephone Administration program (LD10).
Note 2: Do not confuse OPS service with Off-Premise Extension
(OPX) service. OPX service is the provision of an extension to a main
subscriber loop bridged onto the loop at the serving CO or PBX. Do not
confuse CLS OPS (assigned in the analog (500/2500-type) telephone
administration program LD 10) with OPX, which denotes Off-Premise
Extension service.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Application 149