Mounting Brackets; Connector Panels; Bus Termination Cards; Shelf Address Jumper (J50) - General DataComm OCM-2000 Installation & Operation Manual

Shelf Installation

Mounting Brackets

The shelf mounting brackets allow the use of two different Telco frame widths. The brackets are
simply right-angle brackets (longer on one side) designed to mount 19" shelves to 19" frames, or
by reversing the brackets, to adapt the 19" shelf to 23" frames. The brackets also provide center-of-
gravity shelf support and depth adjustment when matched with the appropriate threaded holes
provided in the sides of the shelf.

Connector Panels

When you order a shelf-mounted OCM, it is factory configured for your system with the proper
connector panels installed in the appropriate Zone(s). The shelves and connector panels are listed
in Table 1-1. Zone 1 connector panels are attached to the top of the shelf with six screws. The Zone
3 connector panel is attached at the bottom of the shelf with eight screws.

Bus Termination Cards

The shelf is shipped with two Bus Termination Cards (010P134-001) that provide proper
impedance matching for the data bus on Zone 2. A single shelf has one card inserted into J51 located
at the rear of the shelf
XA20 connector

Shelf Address Jumper (J50)

The shelf address jumper (J50) tells the modules whether they are in an upper shelf or a lower shelf
of a dual shelf OCM. It is located on the rear of the shelf next to J51. After power is removed from
the shelf, jumper J50 (recessed under a protective cover) may be accessed. Set to upper (default
position) for a single shelf OCM. Set to lower if a second shelf is used. See

Expansion Shelf (Dual Shelf Redundancy)

Note
Before adding an expansion shelf, be sure you remove power from the main shelf.
The expansion shelf has no shielded modular jacks in Zone 1. Therefore, you must install the E1/
T1 LIMs in the upper or main shelf.
Adding dual (or expansion) shelves allows up to four power supplies and extra cards in the upper
and lower shelves. A power supply may power either shelf and is called redundancy. For example,
if a dual shelf has three power supplies and any one power supply fails, the remaining two power
supplies provide power for both shelves. Each shelf requires separate AC or DC input power.
Note
IMPORTANT! If you decide to operate two shelves with a single upper power supply (none in the expansion
shelf) and Power Bus Cable installed, do not exceed the load rating of one power supply by installing too
many plug-in cards. With expansion shelf configurations, load sharing always occurs between power
supplies. Refer to the description of the
In a redundant system, the front panel FAIL indicator lights when the supply shuts down due to an
overload condition including an absence of input voltage caused by turning off the power switch on
the supply. If a power supply failure is indicated, turn off the power switch, wait one minute, correct
the overload condition, then turn back on. If the power supply still shows a failure, the power supply
(or a faulty backplane or module) is defective. Power supply failure is also reported to the TMS
Controller.
See the lower view of
directly below the main shelf, with no intervening gap, to allow for inter-shelf cabling.
The optional expansion shelf is not shipped with termination cards. For dual-shelf applications, see
Figure 2-6, and refer to the following text.
036R340-000
Issue 16
(Figure 2-6). The other bus termination card is located inside the shelf in the
(Figure 1-1).
Load Number
Figure 2-6. An MS-1 or MS-1E shelf used for expansion must be mounted
Office Connunications Manager OCM-1000/OCM-2000
Installation & Operation
Shelf Installation
(Figure
described earlier in this chapter.
2-6).
2-11