Product Detail 24 telephone FXS ports with both RJ11 and 50-pin Telco connector Up to 2 SIP server profiles per system and independent account per port Supported voice codecs include G.711, G.723, G.726A/B/E, iLBC, T.38 Fax Carrier grade G.168 line echo cancellation Ideal IP enabler for analog phones, faxes and legacy PBX systems . The "Grandstream 24 Port FXS VoIP Gateway" is best product for you. We recommended Grandstream 24 Port FXS VoIP Gateway