363-206-285
Circuit Pack Descriptions
7-64 Issue 3 June 2001
The MXRVO provides protection switching for the VT-G side of the low-speed
circuit packs. The MXRVO can be requested by the SYSCTL through the intra-
shelf control bus to replace any of the seven service VT-G inputs with the
protection VT-G input. The MXRVO can be requested by the SYSCTL to bridge
any of the seven VT-G service outputs to the protection output.
The MXRVO provides SYSCTL-controlled selectors for the STS-1 side of the
main OLIU protection switch.
The MXRVO provides selectors for an STS-1 timing switch. The timing switch
may be performed autonomously by the MXRVO based on the quality of the
received timing signals or by the SYSCTL.
Fault Detection Circuitry 7
The MXRVO circuit pack has in-service and out-of-service built-in test capability.
In-service testing is continuous and any errors are reported when they occur to
the SYSCTL via the intra-shelf control bus. An out-of-service test is performed
whenever the MXRVO circuit pack is inserted or recovers from a transient failure.
Performance Monitoring 7
The MXRVO circuit pack provides PM circuitry for STS path parameters derived
from B3 coding violations.
Power Circuitry 7
The MXRVO provides power to the corresponding DS1 low-speed circuit packs
associated with the function unit group that the MXRVO is in. It receives two
sources of −48 volts which are diode ORed, fused, and filtered prior to conversion
into a +5 volt source for use by the MXRVO and the low-speed DS1 circuit packs.
A failure of the fuse or converter causes the red FAULT LED to light.
!
CAUTION:
For power reliability, when a muldem is equipped with DS1PM circuit packs,
the associated function unit must be equipped with two MXRVO/STS1E
circuit packs.
MXRVO Quick Reference Summary 7
Transmit Functions 7
The major transmit functions of the MXRVO are as follows:
â– Selects and multiplexes seven VT-G channels into one STS-1 SPE
â– Adds STS-1 path overhead
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