Wiring Tdm Telephony Taps; 2-Wire Vs. 4-Wire; Wiring Schemes - Vidicode APRESA Series Installation Manual

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5.6.

Wiring TDM Telephony TAPS

The interface card that is used to make TDM taps is the DST-card. See chapter 13.2 for the

specification and the connections of this type of interface card.

Almost all enterprise class PBX systems use proprietary protocols to communicate with the attached

telephones.

These telephones are not standard types and can only communicate with the PBX of the same

manufacturer.

The wiring of TDM telephone taps is a little complex. The complexity is not the number of wires to

connect, but in the non standardiszed pinning of the connectors used by the various PBX

manufacturers. Another complicating factor is that besides the familiar 2-wire communication some

manufactures deploy a 4-wire scheme for communication between the PBX and the telephones.

5.6.1.

In case of a 2-Wire connection the communication between telephone and PBX is bi-directional. The

PBX use a ping/pong-type protocol for the voice exchange from telephone to PBX and vice versa (=half

duplex). With the 4-wire connection one pair carries voice information from telephone to PBX while the

other pair does the same, but from PBX to telephone (=full duplex). Note that there is no separate path

for voice and signaling!

The 2-Wire connection uses one recording channel on the APRESA while the 4-Wire connection uses

two recording channels.

This makes the 4-wire connection scheme in terms of channel costs twice as expensive as the 2-Wire

variant, but there is nothing practical that you can do about this.

5.6.2.

The whole issue of wiring TDM telephony TAPS is simply just to identify the wire-pair (or wire pairs) that

carry the voice data and to connect these wires to recording channel(s) on the APRESA.

The first step is to find out the name of the manufacturer and the model number of the PBX and

Telephones.

The TDM wiring taps can be realized in 3 ways:

1. Direct wiring of the RJ21 connector of the interface card (pinning see above)

2. With the RJ11 patch box

3. With the RJ45 patch box

INSTALLATION MANUAL APRESA

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