SER_ROOM [port,] bytes



Although handshaking should ensure that serial input is safe, unfortunately some devices carry on sending data even though they have been told to stop. This may be caused by a buffer attached between the sending and receiving equipment, for example. This is known as ‘serial overrun’ and can have unfortunate consequences, as the receiving equipment may not have room to store the additional information.

Where the system is acting as the receiver, you can use the command SER_ROOM to specify a minimum amount of memory which must be left in the input buffer when the System uses handshaking to check on the validity of the data received. SER_ROOM sets aside bytes in the input buffer which can be used to store information received after the System has told the sending equipment to stop.

If you still find that some data is lost due to serial overrun, try increasing the amount of space. For machines with more than one serial port, you can specify the number of the serial port to be affected by this command (default SER1).


The default room is 32 bytes.


SER_BUFF allows you to alter the size of the input buffer and affects the value set by this command. You should also look at SER_PAUSE.