Telex 38109-977 manual Cable Considerations, RJ12 Modular Plug

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™-CSand 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™-CSmatrices 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

		CONTACTS
RJ12 MODULAR PLUG		Use AMP Chordal
	123456
AMP 5-555042-3 or equivalent		Crimp Tool 231648-1
(View from cable entrance)		or equivalent

LATCH

3 TWISTED PAIR TELEPHONE CABLE

PAIR 1: AUDIO TO MATRIX

PAIR 2: AUDIO FROM MATRIX

PAIR 3: DATA

1	DATA -	1
	AUDIO FROM MATRIX +
2		2
	AUDIO TO MATRIX +
3		3
	AUDIO TO MATRIX -
4		4
	AUDIO FROM MATRIX -
5		5
	DATA +
6		6

DE-9P (MALE)	DE-9S (FEMALE)
TO KEYPANEL	TO INTERCOM SYSTEM*

1		+	1
	DATA	-
2			2
6			6
4		+	4
	AUDIO TO MATRIX	-
5			5
9			9
7		-	7
	AUDIO FROM MATRIX	+
8			8
3			3
	CABLE TYPE:
	BELDEN 8777

IMPORTANT!

*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)

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

C h a p t e r 5 - D e s i g n o f M a t r i x I n t e r c o m S y s t e m s 67