Technical Support

Adjust the Hardware Revision

The hardware revision setting allows the RFC-1/B to compensate for variations in hardware. It is not usually necessary to adjust this setting.

However, due to the location of this setting in memory, it is sometimes overwritten accidently when programming the site identification phrase. The primary side-effect of incorrectly setting the hardware revision is for the RFC-1/B to seize the telephone line as soon as power is applied. The RFC-1/B cannot release the line as long as this setting is incorrect.

It is easy to correct this error but the procedure must be performed from the local phone since the telephone line is seized.


These instructions will reset the hardware version in the RFC-1/B to a setting that works with most systems.

Use the programming security code from your system when prompted at line 3.

  1. Connect to the RFC-1/B from the local phone.
  2. Once you have access to the system, enter programming mode: 80
  3. The RFC-1/B will prompt for the advanced programming security code: 4150
  4. The RFC-1/B will prompt for a four digit address: 0996
  5. The RFC-1/B will repeat the address and wait for a command.
  6. Enter the new setting for the hardware version: 1
  7. Press the pound key to write the data at the address: #
  8. Exit the programming mode immediately by pressing the star key: *

It is important to press * and exit programming mode after the final value is entered.