This ATA is not only a great replacement for the out-of-production Digium IAXy S101i. It is a very compact and versatile ATA that supports both IAX2 and SIP protocols on same device. It also has a built in router, DHCP Server, QoS and many other features. If there are issues running SIP, this ATA will connect via IAX2 (or vice versa). This built-in redundancy makes it an excellent choice for sending to remote locations where SIP/RTP might face unexpected problems.