We had a set of REtevis Model H-777 and have purchase a new set of Retevis walkie talkies (RT27) to add to our set. These do not seem to interact with the older model. Please advise.
RT27 and H777 are analog model radios,for analog radios communication, just set all communication channels with same frequency and CTCSS/DCS is ok. Please download USB universal driver and RT27,H777 software from Retevis official website freely: https://www.retevis.com/resources-center. related video for your reference: https://youtu.be/PEDs3WkxjcM