Mikrotik and VoIP: Fax T.38 transmit problem behind NAT - MikroTik
Amazon.com: 2-Port VoIP SIP Phone Adapter - GT202 Wireless Router, Supports WiFi Asterisk ATA VOS FXS Fax. Suitable for Home or Business (Black) : Office Products
Fax server with T.38 functionality, to communicate with Asterisk : r/sysadmin