GMDSS Maintainer: Element 9

1. A Fax - Group 3 fax via standard voice channel for analog fax applications.
2. B Fax - Group 3 fax via 3.1 kHz audio channel for analog fax applications.
3. C Fax - Group 5 fax via 5.1 kHz audio channel for efax applications.
4. D Fax - Group 3 fax via ISDN channel for analog fax applications.

Tip: press A-D to answer