Unitec Sentine Installation Manual - Manual (Page 20)

S E N T I N E L
Document Number: SENT1001 16
Document Name: Sentinel Installation Manual
3.7 Intercom Systems
3.7.1 Overview
The use of an intercom system allows two-way communications between customers at the Sentinel and
staff elsewhere on site. A customer activates the Sentinel’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.
3.7.2 Intercom Connections
The Intercom has two connectors which control the way in which the intercom is wired and the mode of
operation. J16 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.
3.7.3 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.
3.7.4 Connection Overview
Call Function: The unit will initiate a call function by closing the contacts on RL5. By default, J16-Pin 1
(H1) and J16-Pin 2 (H2) will always reflect the contact closure of RL5. This is the default for the four-wire
mode when both the call function and audio are completely separated. More detailed instructions on this
follow.
Audio: When the Sentinel intercom mode is active, the audio section is floating and is not relative to
ground. By default, J16-Pin 3 (SP+) and J16-Pin 4 (SP-) will always be connected to the audio section.
Four Wire Intercom Configuration: Two separate pairs (four wires) are used for both the call function
and audio in the four-wire configuration. In this mode, J17 receives no jumpers.
3 Wire Intercom Configuration: This mode requires two conductors for audio and one additional
conductor for the call function. This mode uses a common ground for both audio and the call function (SP-
). Jumper pins 3&4 of J17 and connect H1, SP+ and SP- .