ZETRON 640 DAPT XTRA, Installation And Repair Manual, Page: 39 / 210

Hardware Overview
025-9416 27
CAUTION
DID, end-to-end, and ground start matrix configurations do NOT function properly for
the Dual Trunk 4-Wire Audio Interface Board.
Refer to “E&M Trunk Configurations” on page 25 for operational descriptions of this interface.
ROM DISK BOARD
The ROM (read-only memory) disk (Part No. 702-9389) stores all of the paging software for the
peripheral and main processor boards. It plugs directly into an expansion slot on the main
processor board. The paging terminal reads from the ROM disk on power up.
The ROM disk (item #6, Figure 2) consists of four 128KB (1MB configuration) ROM chips in
most applications. It is designed to support a total of eight ROM chips which can be 128KB or
256KB (1M or 2M bit) devices.
Updated software is supplied on a new ROM disk. The single board approach simplifies field
installation of new software.
Jumper Settings
Figure 8 shows the locations of each jumper on the ROM disk board.
To Main Processor
Motherboard
⇓
JP2
1
9
JP1
RAM
ROM
Figure 8. ROM/RAM Disk Board Jumper Locations (Side View)
The jumpers on the ROM disk are used as follows:
JP1 This 9-pin jumper determines the memory configuration for the ROM disk. Four, 2-pin
jumpers should connect the pins, based on the type of memory chips.
For a standard 1MB setup (128KB chips), jumpers should connect pins 2 and 3, 4 and
5, 6 and 7, 8 and 9.
For a 2MB setup (256KB chips), jumpers should connect pins 1 and 2, 3 and 4, 5 and
6, 7 and 8.
JP2 This jumper selects the card as a ROM or RAM disk. The 2-position jumper should be
installed next to the appropriate label.