@Throuput
Yes, correct. What I am referring to is to have a P2P connection over serial line. Meaning transfering coin (transaction) over the serial line. Not only the command interface.


@omegadraconis
You got the idea, unix-like pipe would be a suitable connection .
As to prevent cheating and double spending, I am agree with
you it is hard to prevent in off-line transactions. However, it might be a habit for future bitcoin user to check immediately validity
of an offline transaction with on-line checker. Or they might only accept offline payment from a trusted party only.
It is problem with people and habit when using bitcoin, IMHO.