2-Wire to 4-Wire, Party Line Converter

The COMMS 300 and the openGear version,

Intercom units provides a means to interface

between two channels of 2-wire party-line intercom

audio and two channels of 4-Wire analog line-level

signals. The unit is capable of performing auto nulling

for each channel with the push of a button. In

addition, each of the 4-Wire input and output channel

levels are monitored and displayed on easy to

understand front panel VU meters. With the flip of a

switch the unit can be a +28VDC party-line voltage

power source while providing the 200 ohm intercom

audio termination on both channels. If so desired, the

party-line source and termination can be removed

by just flipping the switch back. The unit can also

be configured to work with either RTS party-line or

Clear Com party-line equipment with the flip of a front

panel control switch. This switch adjusts the output

gain between the party line circuitry and the 4 Wire

line level circuitry depending on which type of units

one is interfacing with.

Auto nulling is done to achieve maximum return

loss between the 4 Wire input and the 4 Wire output


The Intercom unit contains four 5-segment LED

VU meters on the front panel. The first set displays

the 4 Wire input levels for Channel 1 as well as the

4 Wire output levels for Channel 1. The second set

of VU meters display the input and output levels associated

with Channel 2.

The OG-Comms is fully openGear compatible, an

indutry standard card frame, fully SNMP controlable

and monitorable through DashBoard industry standard

software. The openGear frame also offers redundant

power supplies. By adding the MultiDyne OG-Comms

Audio fiber trasport card, a partiline can be extended

over fiber.