Q. I am considering ordering a QL, but wonder whether I will be able to use it with my Star DP510 printer. This has a Centronics interface, but I believe that the QL only has an RS232C port.

My second query concerns an intermittent problem with my Oric hooked up to the Star. When I get a printout from any of my programs, a triangle (ASCII code 245) appears instead of some of the characters.

S. Hazelgrove
Leeds

A. You'll certainly encounter problems linking a QL to your Star - you're quite right about the QL's ports. You would need an adaptor to convert the serial output of the QL to a parallel format. Sinclair Research says that a parallel interface will be available as an optional extra for the QL.

A serial/parallel converter is available from Micropute on 0625-615384 for £115. A more complex buffered interface is available from Mutech on 0225-743289. Micropute's interface has a 2K buffer, while Mutech can offer buffers from 2K (£175) to 32K (£245).

The problem you have with your Oric is probably that the keyboard interrupt routine is occasionally sending erroneous data to the printer port. All you have to do is turn off the keyboard scanning routine with CALL E6CA before sending anything to the printer. To turn it back on, issue a CALL E804.

Using these CALLs in a program has the added bonus of increasing the running speed by up to 20 per cent, useful if you have lengthy calculations or complex string-handling. Do not, however, use a WAIT command between the two CALLs, as WAIT counts keyboard interrupts, and if they've been turned off, you'll be a bit stuck.