How about Ariton ht-842r?

Ariton HT-842R is a low-cost four-port IP voice gateway that can work with most operators ' H.323 or SIP,IP telephony systems and does not need to be upgraded when switching between SIP and H.323 protocols. Provides 4 standard 24V FXS telephone interface, can cooperate with each kind of standard telephone, cordless telephone to use.

The Voice gateway does not need to connect the computer to be able to work, 4 standard 24V FXS RJ11 telephone interface, can cooperate each kind of standard telephone, the cordless telephone use. Two RJ45 Ethernet ports one is connected to the router, and the other is connected to the computer for billing.

Access to the IP Telephony Gateway Web configuration Interface, under the "Phone Settings" section to enable the "Use billing function" and save the settings. Restart the IP voice gateway after the billing function can be opened (if you do not need to charge, do not turn on this feature, after a false reboot will not be able to make the call.) )

Install billing software on any computer in the same LAN, and then set up billing standards and rates in the billing software to be used. Billing software in different time periods and different countries billing methods, users can set rates according to their own needs.