Instruction manual

Hardware Overview
025-9416 15
HARDWARE OVERVIEW
MODEL 640 ARCHITECTURE
The Model 640 consists of several circuit boards in a compact, computer-like chassis. The basic
unit is comprised of the main processor motherboard, a peripheral motherboard, a dual trunk
interface, a ROM disk board, and a RAM disk board. In addition to the standard boards, a TNPP,
TAP outdial, or dual serial board can be added for networking purposes. A second dual trunk
interface can be added, along with MF or dial click decoder options for the trunks. Each of the
standard and optional circuit boards are illustrated and described in the following subsections.
Figure 1 shows a top view photograph of the Model 640 with the top cover removed. The unit
shown has one optional board installed - a second dual trunk card.
Figure 1. Model 640 with Top Cover Removed
Figure 2 and Figure 3 are provided to help locate each of the main components of the Model 640.
Each item in the illustrations is labeled with a number for easy cross-reference from the text in
the following subsections (numbers in parenthesis). See Section 11 for more detailed schematics
and circuit board silkscreens.