Appendix A - System Specifications
800-357-104-01, Revision 01
82
September 29, 2000
HMS-357 List 4 and List 5
To avoid complex calculations, use the following simplified power and fan requirements.
•
If PairGain/ADC components are used and no CPE power is required, the Wideband System 3190 chassis can
power up to 12 doublers without necessitating the use of fans. (Recommended components include the
HLU-319 List 5, the HDU-409, the HRU-402, and the HRU-411.)
•
Chassis configurations that do not use doublers do not require the use of fans. However, NEBS requirements
may restrict the installation to four chassis per rack if no fans are used.
A/B P
OWER
S
OURCES
Each chassis requires one A battery feeds and one B battery feeds rated at a maximum of 30 A each for fully
loaded chassis assemblies capable of driving a full complement of doublers and remote units.
The A/B power feeds provide total backup power for the HXU, HMU, and HFA cards. The HMU, HXU, and
optional HFA have diode-ORed power feeds.
For the HMS-357 List 4 chassis, the line units are powered as a split feed with half of the line units on each battery
feed. A loss of one battery feed forces 14 lines out of service. This reduces the maximum current required per
battery feed for systems with the maximum number of doublers.
For the HMS-357 List 5 chassis, the line units are powered from the backplane through diode-ORed power feeds.
A loss of one power feed will not affect service.
F
USES
System fuses are located in an external fuse tray typically mounted at the top of the CO rack. The HMU reports
all fuse alarms within the WBS-3190. Each chassis within the rack must be equipped with A and B fuses for proper
power protection. Depending upon the system configuration, fuse ratings can vary from 5A to 20A. See
for fuse selection information.
To determine the power requirements of a CO rack, use the guidelines in the following tables:
•
describes the power requirements of various line configurations (A through F) typically
used in a network.
•
shows the power requirements of the common equipment needed for a protected HMS-357.
•
combines this information into the system power requirements for each configuration. Although the
power requirements of the system can vary greatly depending on the line makeup, in practice the line makeup
seldom requires more than 30% of the lines to have doublers. With this type of provisioning, power
limitations due to CO heating is seldom a factor.
ADC does not recommend configurations in excess of 30 A per power feed.
