Table 6-1 Possible Bell Modem Configurations (Public Switched)
Communication Parameters Manual Originate Only Manual Answer Only Manual Originate/ Answer Auto Answer Reverse Channel
300 baud
Full-duplex
2-wire
113A 113D 103A 103A No
113C   103J 103J No
    212A 113B No
      113D No
      212A No
 
1200 baud
Half-duplex
2-wire
    202S 202S Yes
 
1200 baud
Full-duplex
2-wire
    212A 212A No