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Chapter 5 - Design of Matrix Intercom Systems 67
Let’s proceed on the basis that you have now compiled a list of needed equipment, have
gotten approvals, placed the order, and are now ready to begin the installation of your
system.
Cable Considerations
Cabling types do vary considerably among the manufacturers of matrix intercom products,
as do the signals transported by them. For that reason, the following discussion is
somewhat specific to RTS™ Zeus™, ADAM™-CS and ADAM™ matrix intercom
systems.
As noted earlier, RTS™ Matrix Intercom Systems typically use three twisted pair,
unshielded cabling for interconnection. I use the word “typically,” as coaxial cable
adapters are available from Telex to allow keypanels to be connected via coax, but the
standard twisted pair methodology is more cost effective in most cases.
Telex allows the user to choose from two different connector styles for the three pair
connection. The choice is simply a matter of preference by the user. RJ-12 connectors can
be used, and these are readily available, low cost, and quick to assemble.
Note
RJ-12 connectors are sometimes incorrectly referred to as RJ-11 connectors. While they
are basically the same size, RJ-11 connectors have four conductors and RJ-12 connectors
have six conductors.
On the negative side, they are plastic, and not as robust as some installations demand. DB-
9 (actually DE-9, the more proper name) connectors are also provided, and can be used.
These will be more robust, but are also harder to wire, and more expensive. All Telex
®
keypanels have both types of style connectors on them. The type of connector on the
ADAM™ and ADAM™-CS matrices must be specified at the time of order, and can be
either the RJ-12 or the DE-9 style. Zeus comes with DE-9 only.
Figure 5.3
ADAM™ (including ADAM™ CS and Zeus™) Intercom Cable Connections
As seen in Figure 5.3, the wiring takes pin 1 to pin 1, pin 2 to pin 2, and so on, for both
style connectors. What the drawing also shows, and is equally important, is that a given
twisted pair cable carries both portions of the same signal. If you were to wire pin 1 to pin
1, and pin 2 to pin 2, etc., but had one of the wires in a twisted pair carrying +audio in, and
the other wire of that pair carrying -data, the audio would be degraded by having “data
DE-9P (MALE)
TO KEYPANEL
DE-9S (FEMALE)
TO INTERCOM SYSTEM*
CABLETYPE:
BELDEN 8777
1
2
6
4
5
9
7
8
3
1
2
6
4
5
9
7
8
3
DATA
AUDIOTO MATRIX
AUDIO FROM MATRIX
+
-
+
-
-
+
When connecting to an ADAM CS back panel, use
only low-profile cable connectors such as AMP
Part No.747516-3 (Telex Part No.59926-678)
IMPORTANT!
*
3TWISTED PAIR TELEPHONE CABLE
1
2
3
4
5
6
DATA -
1
2
3
4
5
6
AUDIO FROM MATRIX +
AUDIOTO MATRIX -
DATA +
123456
CONTACTS
LATCH
RJ12 MODULAR PLUG
AMP 5-555042-3 or equivalent
(View from cable entrance)
Use AMP Chordal
Crimp Tool
231648-1
or equivalent
PAIR 1: AUDIOTO MATRIX
PAIR 2: AUDIO FROM MATRIX
PAIR 3: DATA
AUDIO FROM MATRIX -
AUDIOTO MATRIX +