- Compatible with fax machines and modem speeds up to 28.8 kbps - Precise dial tone 32V DC talk battery - Switch selectable ring cadence - Provides CPC breaks after hang-up on either port - Switch selectable audio attenuation - Provides 2 seconds of precise dial tone after off-hook - Provides ring back signal to calling device - One or two way ring down capability - Jumber selectable ring count - Ring down and dial tone off mode (ideal for prison phone communications etc.)