My IC-F3400/F5400 Series radio, when programmed with NXDN 15 Bit low level Encryption, will not communicate with older Icom radios (F4261, 4160, etc).

In older models, use CAI 1.2 encryption. IC-F3400/F5400 series use CAI 1.3. To inter-operate between the 2 radios, open the CS-F3400D software and go to Digital/Expert/Compatibility Mode. Program them to CAI 1.2.

16/06/2020