Technical information
Technician’s Handbook
26
OPS Line Card Message Waiting Switches
Set message waiting switches for each circuit (S1 through 
S8) as follows:
Figure 9: OPS Line Card
Table 7: OPS Line Card Switch Settings
Setting Description
A Circuits are connected to Off-Premises (OPS) lines. Loop extended over the 
Message-Waiting Answer (MWA)/Message-Waiting Busy (MWB) pair to the 
called extension.
B Circuits are connected to On-Premises (ONS) lines. Consists of a -140 Vdc 
source delivered at a variable rate to the Ring lead of the called extension. 
Rate is custom programmed during CDE to be continuously on through 80 
Hz.










