User's Manual

Upgrading the Firmware
Reader Software Upgrade Procedure D-5
Final Instructions 1. You must repeat this procedure for each Reader RD21 that is installed on the site.
2. Lyngsoe recommends using the RS232 or RS485 4-wire communication line to upgrade the
Reader’s software (these are more reliable communication links).
3. For more information on the Reader’s RD21 configuration, see Chapter 5, Configuration and
Operation.