System information

INSTALLING THE VOICE MESSAGING SYSTEM 23
To work with the voice messaging system,
each single-line telephone port must meet
two requirements:
• 90 Volt AC ringing, the industry stan-
dard. The single-line port must generate
this ring signal for Lingo to recognize
and answer an “incoming” call.
• DTMF (touchtone) signals must be
passed to Lingo ports through the
single-line port. In addition, the tele-
phone system must be able to receive
and interpret the DTMF signals that
Lingo transmits.
Your customer’s telephone system provides
single-line support in one of three ways:
• Internal cards
• External modules
• Built-in support
Internal cards
Some telephone systems provide single-
line support by using a special card that
is installed in the telephone system cabi-
net. The single lines supplied by the card
are connected to the telephone system’s
main distribution frame (MDF—usually
a series of punchdown terminal blocks)
by using a standard Amphenol connector
and a 25-pair cable. Lingo ports connect
to the telephone system’s single-line ports
through the MDF.
Some single-line cards include AC
ringing and DTMF signaling. In other
cases, the telephone system may require
an AC ring generator, an added DTMF
receiver/generator card, or both.
TELEPHONE SYSTEM REQUIREMENTS