If you have a RT21,while other radios are different types from yours , what should you do?Do not worry,that is easy to communicate with them,
please read the method below,let us take RT6 as an example.
Step 1: programming RT21 radio
For example: In channel one
CTC/DCS DEC: off
TX frequency : 462.23750
CTC/DCS ENC: off
Note: You can set up the CTCSS according to your needs, CTCSS will keep your communication privacy.You need to know, two analog radios can work together under same frequency and same CTCSS.
Step 2： Programming RT6 radio
You can programme RT6 by hand or in RT6 software
RT6 walkie talkies have the keypad, so that you can program your frequency manually.Just set up to same frequency and CTCSS with RT21 walkie talkies.Or you can through PC to program frequency and CTCSS on every channel.
Step 3: after step 1 and step 2 done, RT21 will work with RT6
All in all,if you have the different radio, if they have are same system,and also have the frequency segment, you can make them work together by programming to same frequency and same CTCSS.