This is regarding RS 232 interface. 

* Two computers C1 and C2 , that exchange synchronous data , are
connected via a radio/satellite link:
C1-ModemM1-Radio-M2-M3-Satellite-M4-C2

*Mi's are modems.

* M1-M2, and M3-M4  are both analog ( like a phone line except that
they are radio and satellite based, respectively). Rest is digital, RS
232C complaint. ( Satellite companies don't like direct feed of radio
since it might damage their equipment; M2 converts west -> east
traffic to digital and M3 gets this data and feeds to satellite.
Similarly, one can explain east->west flow.)

* Design M2-M3 cable ( known as null computer).

* Can the C1-C2 be a swtiched cnnection? Explain either way.

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Clarification of Question by anshul2579-ga on 20 Sep 2004 16:59 PDT

Design the M2-M3 cable ,
write the data transfer equations ( DTR-->...<-- DSR etc)and answer if
C1-C2( the whole thing) can be a switched connection ...with the
reason to support your answer.