The serial number of my modem (56k ZOOM/FAX MODEM EXTERNAL)


I´m sending commands to the modem via a particular software.
When I configure the serial port of the PC at 9600,Even parity,7 bits and 1 bit of stop the modem sends me a "0" as responses of the commands.
If I configure the serial port as (9600,None,8,1) there is no problem too.
When I configure the serial port as (9600, Odd, 8, 1) if I send the command ATL0 to the modem it respondes me with a "?B".
And when I configure the serial port of the PC as (9600,Even,8,1) if I send a command to the modem it doesn´t respond nothing, and it doesn´t make the action indicated by the command. I´ve tried with the HyperTerminal of Windows and with this configuration it doesn´t work well, but with the others there´s no problem.

1 - Is it necessary to configure the modem in a special way in order to work with 9600 bps, Even or Odd parity, 8 bits/character, 1 bit of stop.?
2- The modem takes this information of the serial port, doesn´t it ?
3- Why the others configuration works well and only the especificated two fails down ?

Thanks and Regards