AT&T SYSTEM 25 Manual page 138

Extending Calls (Unannounced)
Extending a call consists of placing an active call on temporary hold (splitting), placing
another call to an inside party or an outside number, and then connecting the two calls
together. The attendant can choose to put the call through without announcing the
call first. Unanswered calls return to the attendant console for further handling. For
information on extending calls and announcing it to the called party, see the entry,
"Extending Calls (Announced), " on page 3-17.
The attendant extends calls for the following reasons:
A party on a trunk call wants to be connected to a station inside the system.
A party inside the system wants to be connected to an outside number via a
trunk.
A party inside the system wants to be connected to another inside station (an
unusual procedure because inside users can easily call each other directly).
SLAC consoles are administered to have either Automatic Release or Automatic Hold. If the
system is set up for Automatic Release, the SLAC attendant can drop out of a call simply by
pressing another LOOP button. See the entry for "Automatic Release and Automatic Hold"
on page 3-5 for more information about these features.
If the attendant extends a call from outside System 25 to a busy voice terminal, the caller
will be placed on hold and the called party will hear a tone that indicates they have a
waiting (camped-on) call. If the person chooses not to take the call, it will return to the
attendant after a preset interval.
In general, the attendant should not use TRANSFER to extend calls; if TRANSFER is used,
busy or unanswered calls will not return to the attendant console for further handling. The
exception is when the attendant wants to extend an incoming trunk call to another trunk.
For more information about trunk-to-trunk transfers, see the "Transfer" entry in Section 2,
"Voice Terminal Features."
Extending Calls (Unannounced) 3-21