GAI-Tronics Electro Sound Electro-Sound Communication System - Manual (Page 5)

Pub. 42004-072D
Electro-Sound Communications System Page: 5 of 9
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Two-System Interfacing
Electro-Sound can be connected to a Page/Party
®
system by means of a Model 370-202 Interface. The
interface amplifier will match the Electro-Sound transmission line operating at 1000 ohms and one volt ac
and a Page/Party
® system operating at 33 ohms and one volt ac. Gain is adjustable in either direction and
is factory adjusted before shipment. A line balance control is included and should be adjusted once at the
time of system start-up.
Interconnecting wires include: one twisted pair for ac power, 115 volts, 60 Hz; one twisted pair for page;
one twisted pair for party; and one twisted pair for Electro-Sound. Minimum wire size should be
No. 14 AWG for the power and No. 18 AWG for the others. The interface should be located within
300 feet of the line balance assembly of the Page/Party
®
system. See Figure 6.
The twisted pair for the Electro-Sound shall be kept separated from the other wiring in the enclosure, and it
shall not be included in any conduit, cable, or cable tray with the other wiring in the enclosure. Wiring
foreign to the operation of the system shall not be associated in any way with the interconnecting cable or
wiring, nor shall it be fed into or through the interface enclosure. The interface enclosure and conduit shall
not be used to ground any other piece of equipment.
Figure 6.
Installation
This section concerns installation of an Electro-Sound system. It contains considerable detail on the power
source location, minimum wire size, and maximum line-length vs. number of stations in use. There are five
main points to planning and installing:
• The power source should be located near the electrical load center of the system.
• Use cable with twisted conductors.
• Use the appropriate wire size.
• Do not locate the cable in same conduit or cable tray used for power wiring.
• Do not attempt to operate more than 15 handsets, headsets, or permanent stations at any one time. This
is due to current limiting within the power source and does not limit the number of jack stations that
might be installed.