... audio and data channels, multiple cards include: FXS, FXO, hotline, magneto phone, 2100Hz carrier phone, 2 wire E/M, 4 wire E/M ... 220V AC is optional, supports dual power supply Common Cards Audio Service sub-channel cards-FXO card: provides 4 channels FXO ... FXS interface- 4-wire E&M audio card: provides 4 ch 4-wire E/M interface, supports E/M signaling-Magneto card: provides 4 ...