Clear-Com TWC-704 - Manual (Page 8)

T W C - 7 0 1 A N D T W C - 7 0 4 A D A P T O R S 1 - 2
TWC-701 AND TWC-704 SYSTEM
The TWC-701 is a stand-alone adaptor that combines two standard Clear-Com
intercom channels (on two separate cables) onto a single standard 3-pin
microphone cable. It does this by combining one channel of intercom audio with
the 30 volts DC operating power.
The TWC-704 adaptor is four channels of the TWC-701 in a single 19-inch
rack mount chassis.
Clear-Com intercom products with TW functionality accept two individual
channels of intercom from one single 3-pin cable. TW functionality in those
products separates the intecom audio from the DC operating power.
If a TW-equipped station is connected to a standard Clear-Com intercom line
(without a TW circuit), only the Channel B portion of the station will operate
normally. Channel A will appear to be inactive. Channel B intercom audio and
“call” signaling is simply passed through the TWC-701 to the intercom station,
and operates in the normal Clear-Com manner.
Because the Clear-Com “call” signal function is normally accomplished by
applying a DC voltage to the intercom audio line, call signaling is deleted from
the Channel A line. When using TW-compatible devices, both channels will
receive and transmit a call signal.
See the RS-601 and RS-603/623/R beltpack manuals for additional TW product
support.
Note: “TW” is the designation Clear-Com uses for the system of combining the
30 volts DC operating power with the intercom audio. “TW” is derived
from the “two-wire” because by combining the intercom audio with the
DC operating power, a single channel of intercom–with the required
operating power–can be run on only two conductors. However, because
the intercom line is unbalanced audio, Clear-Com does not promote the
use of single-channel operation on two unshielded conductors (i.e.
“twisted pair”). If you have a specific application that requires actual
two-wire operation, please contact the factory (510-337-6600) for
further information.
Figure 1-1: A typical system
TWC-704
TWC-701
(A3F)
(A3F)
Line Splitter
RS-603
(mono) RS-623R
(stereo)
To additional
“TW” remote
stations
(A3F)
Channel A
Channel B