AT&T SYSTEM 25 Manual page 33

Up to 32 coverage groups can be established using coverage group numbers 1 through 32.
Each group can have up to eight receivers. There is no limit on the number of senders, but
each sender can be covered by only one group. Coverage group senders may also receive
individual coverage or be assigned to a pickup group.
The System Administrator can administer a voice terminal to send call ringing to coverage
while its user is busy on another call. In this case, calls to an off-hook multiline voice
terminal with an idle System Access button will start ringing at the covering terminal after a
single burst of ringing at the covered voice terminal; if there is no idle Cover button, the
system will check periodically for an idle Cover button and ring at the first available coverage
receiver. If all System Access buttons on a multiline voice terminal are busy, the call will go
immediately to an idle Cover button; if there is no idle Cover button, the calling party
receives busy tone. Calls directed to an off-hook single-line voice terminal will start ringing
immediately at the covering terminal; if there is no idle Cover button, the calling party will
receive busy tone.
The System Administrator can also administer a voice terminal to send call ringing to
coverage when its user does not answer a call. Calls sent to coverage continue to ring at
single-line sender terminals, but will stop ringing at multiline sender terminals. However,
calls sent to coverage from a multiline voice terminal remain on the incoming call appearance
button, and can be entered by the called (sender) station. If all System Access buttons are
busy, additional calls sent to coverage are not accessible at the multiline voice terminal.
DGC Coverage Group Receivers
With DGC Group Coverage, an established DGC group serves as the coverage receiver for all
senders in the coverage group. There is no limit on the number of senders, but each sender
can be covered by only one group.
DGC receiver groups are first set up as standard DGC groups, numbered 1 through 32. Each
DGC group can have up to twenty members. Members can be assigned multiline or single-
line voice terminals.
DGC coverage groups can then be specified using coverage group numbers 101 through 132,
where coverage group 101 has DGC group 1 as its receiver group, coverage group 102 has
DGC group 2 as its receiver group, and so on. No button assignments are required.
Calls sent to a DGC coverage group hunt in a circular fashion for the first idle station,
starting after the last station to receive a call. If all DGC members are busy, calls continue
to ring and/or flash at the covered station and at any individual coverage receiver's station
until a DGC station becomes idle. Once a call is directed to a DGC member, it is no longer
accessible at the sender station nor at any individual coverage receiver. Calls sent by
coverage to a DGC coverage group member do not receive additional coverage.
2-20 Voice Terminal Features