The upgrade firmware has solved the prolem as below :
when group intercom function switch on (above 3 riders and including 3 riders) , press volume - may close the voice channel
Tel: 86-755-2328 6960
Office Address: Room 603,Xingji Tower,Shangde Road,Bao'an District,Shenzhen, China.
Copyright ©2016 Success ETC Technology Co.,Ltd