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ADCP-61-814 • Issue 1 • April 1999
Page 8
© 1999, ADC Telecommunications, Inc.
2.2.4 Rear Interface Units
The RIU, mounted in the rear of the chassis, provides the interface for the coaxial cable and
the jack access card which is plugged into the RIU from the front of the chassis. The interface
connectors accept coaxial cable terminated with F or BNC connectors. See Figure 9. The RIU
is factory wired with
±
5 V and ground for powering the jack access card when it is plugged
into the RIU. The
±
5 V is passed to the jack access card through pins while the ground is
connected through the RIU and card bodies.
6772-C
REAR
INTERFACE
UNIT
FROM VIDEO
TRANSPORT
SYSTEM
TO VIDEO
MODULATOR
JACK
ACCESS
CARD
Figure 9. RIU and Jack Access Card
2.2.5 AVIS Jack Access and Amplifier Cards
There are three basic card circuit configurations available:
•A passive (–20dB) card with Monitor, IN and OUT little coax jacks for full jack access.
•An active (0 dB baseband video) card with Monitor, IN and OUT little coax jacks for
full jack access.
•Active (0, +10 and +20 dB gain amplifier) cards without access jacks.
PWR-AVIS Cards, except for the 0,10 and 20 dB active (amplifier) cards, provide the means to
access circuits for monitoring and maintenance functions or to amplify an incoming signal. See
Figure 10. The monitor network circuitry for the active and passive cards provides access to the
signal at 0 or -20 dB level respectively. The active card provides a 0 dB unity gain signal with
respect to the output signal. The active amplifier cards provide fixed gain of 0, 10 and 20 dB
respectively and are for return path application with bandwidth of 5 MHz to 200 MHz. Power (
±
5
V) and ground for active cards is automatically transferred from the RIU when the card is
plugged in. The cards with jack circuitry automatically provide 75-ohm circuit termination.