RS232 (V24) Communication RS232 serial lines may be used for point to point communication between two machines. In this case, the RPC system runs a simple protocol over the line. There are various options available to optimise the protocol given the capabilities of the systems in use. The address format is The < device > is, under VAX/VMS a logical device name, but otherwise of the form TTn where n is the channel number: The options are optional single letters as follows. They are not all supported on all systems.

B
Binary coding method: use all 8 bits of the communication path. This is the default. This is faster than the alternative "L" option, but is not possible with some systems because of operating system restrictions. If the serial line runs over multiplexers, then they might also restrict the use of the line so that 8 bit communication cannot be used. In this case the alternative option (L) must be used.
L
Printable ASCII coding method: use only the printable ASCII characters (seven bits). This is slower, but does not require the operating system to pass control characters undamaged.
R
A strict handshake is used for flow control, for the benefit of those systems with inadequate input buffering. If both connected systems have sufficient input buffering, the F option may be used to make the protocol run faster. The default varies from system to system.
F
Disables the handshake protocol. Alternative to R.
C n
Selects (for PCs, Monica and Macintosh) the communications channel. "n" is either 1 or 2.
S n
Selects, where this is possible, the baud rate. "n" must be the baud rate required in decimal, e.g. S300 or S9600
These options are specified in the RPC address string, just before the ".V24" medium specifier. See details in the section about your particular system@@..