&03 (3) select output stream

OSByte call Action Available on:
(dec) (hex) BBC Master Electron
3 03 Select output stream x x x

Entry parameters

X The output device(s)

On exit:

X Old value

This call selects the output streams to be used. The X register contains the streams to use, one per bit:

Bit Output selected if bit is set
0 Enables RS423 driver
1 Disabled VDU driver
2 Disabled printer driver
3 Enables printer, independent on CTRL B/C or VDU 2,3
4 Disables spooled output
5 Not used
6 Disables printer driver unless char is preceded by VDU 1
7 Not used

*FX 3,0 selects the default output:

  • RS423 disabled
  • VDU enabled
  • Printer enabled if selected by VDU 2
  • Spooled output enabled if selected by *SPOOL


Bit 3 should not be used to enable the printer as it might conflict with Econet claiming the printer.


If RS423 or printer output is selected on the Electron a paged ROM service call is issued. If no suitable response is received the output is thrown away.