Monroe Electronics R177 - Manual (Page 4)

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General Description
Developed especially for the small cable operator, the model R177 offers inexpensive baseband
switching for full screen and audio replacement in full compliance with FCC EAS requirements.
Available in two configurations; “Master” (R177M) and “Slave Monaural” (R177S), both units
provide amplification and switching of baseband audio follow video signals and allow the
insertion of audio and video from an EAS control system into all the channels at a cable
headend.
When the proper alert codes are received by the EAS system, baseband video signals from
each channel are switched from the programs they normally show to the alarm video provided
by a character generator. Audio is similarly switched. When the EAS alert (or test) has
concluded the unit(s) switch back to the program audio and video. Switching of the audio
signals and video signals can be done independently if desired.
Each unit has eight audio and video switches. EAS Audio and Video signals are buffered with
adjustable ±3 dB amplifiers for isolation and signal quality. Individual test switches allow
separate testing of the audio and video relays in the unit, allowing less intrusive testing when
desired.
The modularity of the design, with 8 complete switch pairs per unit, allows the operator to mount
the unit where he can minimize cable runs and complexity. Mounting it on the rear of the
equipment rack saves valuable space for other uses.
R177M
The Model R177M Master Baseband Switch is the “master” unit and provides balanced stereo
audio follow baseband video switching on a contact closure. The baseband video, audio
signals, and control signals are looped through to supply succeeding units.
High quality and long life RF and Audio switching relays ensure low loss and high isolation for
reliable system performance.
Control of this unit to switch audio, video, or both, passes through to any succeeding units for
EAS alarm switching.
The R177M can also be used as a “stereo slave” unit.
R177S
The Model R177S Stereo Baseband Switch operates as a “slave” unit with the Model R177M
unit. It provides balanced monaural audio and wide bandwidth baseband video switching.
The “loop through” video and audio signals are internally buffered with an audio gain
adjustment.
Switching relays provide isolation and signal handling capabilities to satisfy any user
requirements.