P O R T A L T I +
Portal Installation Manual
27
Document #: PTL1001
3.8
Intercom Systems
3.8.1
Overview
The use of an intercom system allows two-way communications between customers at the
Portal and staff elsewhere on site. A customer activates the Portal’s intercom output by
pressing the help button. Without an intercom, the intercom output can be used to activate a
bell, light or other device to alert an attendant that help is needed.
The intercom wires connect to the Display IO board on the back of the main door. Jumpers
and adjustments to control its operation are also located on that board. 2, 3, and 4 wire
intercoms are supported. A digital intercom is recommended if the intercom wiring is sharing
conduit with other communications wiring, but not required. Unitec does not supply intercom
systems.
3.8.2
Intercom Connections
The Intercom has two connectors which control the way in which the intercom is wired and
the
mode of operation. J34 is the interface and connects to the customer’s intercom unit. J35
is used to select mode of operation (two, three, or four wire intercom systems). Twisted pair /
fully shielded cable is recommended for optimum performance.
3.8.3
Intercom Adjustments
The Intercom system has the ability to sense when voice band audio signals are present.
This allows the speakers in the unit to revert to a passive intercom mode. This bypasses the
internal audio section and allows the left speaker to be used as an intercom. The sensitivity
and time delay of this mode can be adjusted according to the local acoustical characteristics,
such as background noise.
Sensitivity Adjustment:
R169 is used to adjust the sensitivity of this circuit. A
green LED below the la
bel “SENS” will aid in the Sensitivity Adjustment.
Time-Out Delay Adjustment:
R144 is used to adjust the time-out delay after
which the XPT will revert back to the normal audio mode. A green LED below the
label “DELAY” will aid in the Time-Out Delay Adjustment. Adjust R144 to the
desired delay after the last audio has been detected. Thirty seconds is normal.