Hi all experts, I have a Grandstream ATA-386 device. Elastix could detect it. One port I have connected to Polycom soundstation which work without issue. The other port I connect to a Brother all-in-one machine. It can send fax internally (dial extension within office) through the ATA devices. However, when fax to external through the PSTN (Openvox T1 card), it fails, it can get the connect beep sound but fax machine show communication error. Anyone know how to solve this? Is it Openvox card issue or Elastix setting? By the way, I have tested it works well with my production platform running Asterisk 1.2 + Digium card.