Hi ,we are zhengzhouyuneng co,.ltd in china .Our main products are viop ,and they are all in high quality and low price .
Ip phone ；support sip ,h323,iax2
Voicegateway:support sip ,RFC3261,RFC2543
Single ,double ,4 ports .
If you are interested with them ,pls contact me .
My msn is email@example.com
Our website is www.yntx.com