AT&T MERLIN LEGEND System Reference Manual page 144

Features
When Group Coverage is the only type of coverage programmed for a
sender, the QCC queue should not be programmed in addition to Group
Cover buttons because coverage calls received by a QCC system operator
cannot be programmed for Delayed Ring. Therefore, eligible calls ring
immediately both at the sender's telephone and at the QCC queue. This may
not allow the sender enough time to answer the call before a QCC system
operator receives the call.
A maximum of one calling group can be assigned as a receiver for each
coverage group.
If a calling group is programmed as a receiver for a coverage group, it is the
only Group Coverage receiver and no other types of Group Coverage
receivers can be programmed. However, Individual Coverage (primary and
secondary) can also be programmed.
A calling group can be a receiver for 1-30 coverage groups.
When a sender is assigned to a coverage group and no receivers are
assigned for the group, if the sender is unavailable, the caller hears ringback
and not a busy tone.
Primary Cover, Secondary Cover, and Group Cover buttons cannot be used
to make calls.
A Group Coverage receiver can program a Group Cover button and can also
be a member of the coverage group for which the button is programmed.
Calls for the receiver are sent to all receivers programmed for the group.
Only one extension can be assigned as the principal user for each individual
line/trunk assigned as a personal line.
If a call is sent to coverage because the sender did not have available
buttons to take the call, the call does not return to the sender's telephone,
even if a button becomes available while the call is ringing at a coverage
receiver's telephone.
The factory setting for the Coverage Delay Interval is three rings. The setting
can be programmed for 1-9 rings.
The Coverage Delay Interval does not appear on system programming
reports.
The Secondary Delay (the delay before a call is eligible to ring at a
Secondary Cover button) is fixed at two rings.
The duration of the ring heard by an outside caller is shorter than the ring
heard at an MLX or analog multiline telephone. Therefore, an outside caller
hears one or two rings plus the number of rings programmed for the Delayed
Ring Interval and Coverage Delay Interval. For example, if the Delayed Ring
Interval is programmed for two rings and the Coverage Delay lnterval is
programmed for one ring, an outside caller hears four rings before the call is
sent to coverage. If both intervals are set to their maximum values, the caller
can hear up to two additional rings.
If a receiver has both a Primary (or Secondary) Cover button for a sender
and a Group Cover button for the group in which the sender is a member, a
call rings only at the Primary (or Secondary) Cover button. This prevents
multiple calls to the same receiver.
Coverage 2-95