Custom Modem Setup for Mainframe or Minicomputer Host

Host Limitation                        Hayes Solution                                  



Can not control DTR or issue escape    Select &D0: Modem ignores changes in DTR     


sequence with guard time               status (factory setting)                         




Can reset itself but not the modem     Select &D1: Modem enters command state when  


											 on-to-off transition of DTR is detected.         




DTR timing is not adjustable           Adjust register S25 delay time                  




Unable to monitor carrier (older IBM   Select &S1: Handshake asserted prior to      


Hosts)                                 handshake negotiation                            



 


Must see DSR at all times 				 Select &S0: DSR always asserted  


VAX systems)            



Timing does not support lengthy        Select &S2: DSR asserted after handshake     


handshakes (associated with some       negotiation, but before CONNECT result code is   


high-speed modems)                     sent to DTE. Also select a specific negotiation  


											 handshake option (N command option.) which       


											 specifically matches the modem combinations.     




Must see CTS to be able to talk to     Select &Rn:ignore  


modem                                  RTS; always assume presence of CTS.              




RTS/CTS timing not adjustable          Adjust S26 RTS-to-CTS delay time                




Not able to recognize FDX modem on     Adjust S26 RTS-to-CTS delay time                


2-wire telephone line