Introduction

The VSI as shipped from the factory is configured to the RS-232C specifications. This means it accepts and outputs a +/-10 VDC signal for serial communication. The Decatur type radar output a serial data stream at +5VDC and ground. This is compatible with the VSI if IC U4 is removed and the holes for its Pin 8 and 9 jumpered. This allows the Decatur signal to go directly to the VSI UART which accepts +5VDC and ground serial data in the RS-232 format. If the VSI is ordered for the +5VDC and ground interface a socket will be substituted for U4 and the jumper installed at the factory. If the VSI is to be converted back to normal operation, the jumper must be removed and IC 4 reinstalled.

Caution should be exercised when removing or installing U4. Make sure a static free area is established prior to the operation or permanent damage must result to the VSI or IC U4.

NOTE: New models of Decatur Radar Units do not require the above modification. They accept the standard RS-232 signal directly from the VSI. Consult your manual or the Decatur factory if you are in question.

VSI Dipswitch Settings

• SW1-on for 9 line speed history
     off for one line updated
• SW2-off
• SW3-off
• SW4-on
• SW5-off
• SW6-off
• SW7-on
• SW8-on

Wiring