Clear-Com EF-701M - Manual (Page 48)

4 - 2 E F - 7 0 1 M I N T E R F A C E
The EF-701M Interface connects 2-wire intercom systems or stations together over
various 4-wire transmission media. In doing so, it converts a channel of standard 2-wire
or TW party line to 4-wire audio and, at the same time, converts a DC-voltage call signal
or 20-kHz call signal to RS-422 data.
Local PL : The party-line system that connects to an EF-701M through standard
microphone cable and powers the EF-701M Interface.
Matrix Frame : A matrix frame holds the programmable circuit cards which control an
intercom system. The circuit cards connect to external intercom devices (stations,
interfaces, 4-wire audio) through the RJ-45 connectors on the back panel. Each RJ-45
connector is called a “port”.
Metric Conversions : The following table gives common metric conversions.
Modem : MODulator/DEModulator. A device for converting an analog signal to/from a
digital or optical signal for transmission and distribution over various media and
networks.
U.S. to Metric Measurement Metric to U.S. Measurement
1 inch = 25.4 millimeters 1 millimeter = .04 inch
1 foot = 0.30 meter 1 meter = 3.3 feet
1 mile = 1.6 kilometers 1 kilometer = 0.62 miles