Codan 8525B Series Handbook page 107

Using tone call
Tones t1 and t2 are given values in the factory. You can override
these settings by using the following set-up procedure. To
reinstate the original values, either enter '0' frequency or delete
the latest channel information.
All displays in this section show examples of channel and
frequency numbers. You must insert your selected channel and
frequency numbers.
8-2 Outback HF Radiophone