AT&T MERLIN LEGEND System Reference Manual page 116

Features
Key and Behind Switch
Considerations
Feature Interactions
Callback
Camp-on
Conference
Coverage
If a multiline telephone in the Key or Behind Switch mode does not have an
Intercom Originate Only button assigned or available, the user cannot pickup
the waiting call.
Call Waiting is not activated if a line button of the appropriate type (such as
Intercom or System Access) is available to receive a call.
A telephone can have more than one call waiting at a time.
If a user is in the process of dialing and Call Waiting is being used to reach
the user, the touch-tones generated by the dialpad cancel the Call Waiting
tone. As a result, the user may not be aware that a call is waiting.
If a single-line telephone with a timed disconnect is used (for example AT&T
models 2500YMGK-PEC 3178-NHL and 2500MMGK-PEC 3101-ETR),
pressing the switchhook automatically disconnects the call. With this type of
telephone, the Recall button must be used instead of the switchhook to put
the current call on hold and answer the new call.
An extension programmed as a fax port can activate Call Waiting so callers
can wait until a fax machine is available. To prevent disruption of an in-
progress fax message, a Call Waiting tone is not sent to an extension
programmed as a fax port.
When automatic Callback is used to queue a call at an extension that has Call
Waiting, Callback overrides Call Waiting. The user with Call Waiting does not
hear the Call Waiting tone, and the call is queued until the extension becomes
available.
A user with no available buttons to receive a transferred call hears the Call
Waiting tone when a co-worker uses Camp-On to transfer a call, even if Call
Waiting is not activated.
A Call Waiting tone is only heard by the person receiving the call and not by
other conference participants. If the conference originator reaches a busy
extension, hears the call waiting special ringback, and tries to add the call to the
conference, the system returns a busy tone. The user must press the Drop
button and then press the line button used to call the busy extension to drop the
busy tone from the conference.
A call to a sender with Call Waiting activated goes to Individual and/or Group
Coverage first. If all coverage areas are busy, the sender receives the Call
Waiting tone.
If a sender uses Coverage On/Off to prevent calls from going to Coverage
receivers after hearing a Call Waiting tone, the waiting call does not go to
Coverage, but subsequent calls do.
Call Waiting 2-67