AT&T System 25 - Manual (Page 32)

on-hook
PDC
a telephone is on-hook when the handset is
in its cradle, depressing the switchhook
button.
outside call call between a System 25 telephone and a
telephone not connected to System 25.
Outside calls are made over Central Office
or other trunks and are signalled by two
short rings.
outside line a trunk (line) to the Central Office or other
system. Outside lines may be accessed by
dialing an access code.
(Personal Dial Code) extension number that
is assigned to an individual, and is normally
paging
park
pickup
program
associated with the telephone at the
individual’s desk.
feature that allows you to access paging
equipment from System 25 telephones.
feature like hold except that it allows you
answer the call from any telephone. to
feature that allows you to answer a call that
is ringing at another telephone.
ability to store a telephone number or
account code so you can access it by dialing
a code.
queueing tone five short tones indicating that your request
for callback has been confirmed.
recall button on some telephones that may be
pressed instead of the switchhook.
ringback tone repeating on/off tone indicating that the
number you dialed is ringing.
special ringback one long tone followed by one short, dull
tone tone indicating that the person you dialed is
busy and has Call Waiting.
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