Technical data

8-16

VMEbus Backplane

VMEbus Interconnectivity

The slots of the backplane are interconnected in accordance with

the VME specification, with exception of the autojumpering and

active termination.

All rows of the J1 bus connectors (A, B, C) are interconnected across

all backplane slots, providing the required signals for A24/D16

operation. The center row (B) of the J2 bus connectors is

interconnected across all slots, providing the required signals for

extended operation (A32/D32). Rows A and C of the J2 bus

connectors are not interconnected, but are available to the user for

I/O functions or expansion bus operation.

Backplane Power

VMEmodules that plug into the backplane may require voltages of

+5Vdc, +12Vdc, and –12Vdc for operation. The power supply’s

output connector plugs directly into the backplane, which

distributes the power directly to the VMEmodules.

The backplane also distributes DC power to one optional SCSI

Device Storage Module (as well as the system’s VMEmodule disk

or tape drives).

The backplane of the 3-slot system accommodates up to two 3

/2-

inch half-height storage devices above the VMEmodule installation

area.

The backplane of the 12-slot chassis accommodates up to five 5 1/4-

inch half-height storage devices to the left of the VMEmodule

installation area.

The 20- and dual 9-slot chassis use VME mass storage modules

(consisting of two 3 1/2-inch half-height drives — a hard disk drive

together with an optional diskette, data cassette, or DAT drive —

mounted on a VME board), which plug into the VME backplane. If

installed, the VME drive modules occupy three slot positions each.