We are voip device manufacturer in China.Our MODEL for sip phone is GF101/GW102 , Which support h.323 ,mgcp and iax2 too. it supports all kinds of sip system like ASTERISK etc. Many USA, italy , singapore and other countries' company are using our sip phone for their sip system.
As for the  GW101/GW102, which is a 1 FXS with lifeline ATA and suitable for sip system like our sip phone cause they are using the same chip .

archfish
Sales and Marketing Dept.
Shenzhen Goldenfuture Technology Co.,ltd,China
Email:archfish@goldenfuture.com.cn
Msn:archfish1213@hotmail.com
Skype:archfish
Tel: +86 755 26506933
Fax: +86 755 26504895
http://www.goldenfuture.com.cn