Clear-Com PL-PRO EF-1M, Инструкция по эксплуатации

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E F - 1 M I N T E R F A C E 2 - 3
CONVERTING A PARTY-LINE CHANNEL TO 4-WIRE AUDIO
The EF-1M Interface converts a channel of standard 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. This 4-wire audio and RS-422 data can then be sent to a fiber-optic converter
(modem); over copper, unshielded twisted-pair (UTP) cable such as Category 3, 5, or
above; or it can simply be used as an excellent stand alone 2-wire to 4-wire converter. In
most cases though, EF-1M units will be used in pairs, because once the signal is converted
to go over the chosen transmission medium, it must be reconverted to 2-wire mode to
properly connect to the party-line system or station at the other end of the line. The
EF-1M obtains its DC operating current from the local party-line connection on pin 2 of
the XLR connector. This current is not conducted between EF-1M units, so each EF-1M
must be powered by an intercom line as shown in Figure 2.
Figure 2: Each EF-1M unit must be powered by an intercom line
3
3
= Male 3-Pin XLR
= Female 3-Pin XLR
Party-Line Intercom EF-1M EF-1M Fiber Modems
Party-Line Intercom
Cat 3 or Cat 5
Twisted Pair
3 DB15
3 3
3
3 DB15 3 3
The EF-1M converts
standard 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.