What Does Group 4 Protocols Mean?

Group 4 protocols are a protocol suite used to send fax documents over ISDN networks supporting images up to 400 dpi resolution. It is designed for FAX transmissions between ISDN 64 kbps systems and for using protocols.

Techopedia Explains Group 4 Protocols

Group 4 Protocols include the following protocols:

  • T.6
  • T.62
  • T.70
  • T.72
  • T.411
  • T.412
  • T.414
  • T.415
  • T.416
  • T.417
  • T.503
  • T.521
  • T.563

Group 4 faxing connections between source and destination are digital in nature. For instance, an office may use a PBX base telephone system which is digital and the telephone carrier might use digital connections. In such cases, it is always a better option if there is at least a little analog communication in the circuit between local telephone service and PBX. Until telephone systems are converted to digital networks, the group 4 fax systems cannot replace Group 3 systems.