|★ HARDWARE ★ PERIPHERIQUES ★ KDS 8 bit printer port interface ★|
|Imprimante Divers - Kds - 8 Bit Printer Port Interface|Amstrad Computer User)||Hardware Peripheriques|
The Mk 1 version of the KDS 8 bit printer port was incompatible with CP/M, and some programs would not work properly when the port was connected,
It consists of a very neat printed circuit board, about 4cm square, containing two chips, two capacitors and a resistor. In addition it has an edge connector providing a new output for the printer.
Installation is simplicity itself - just a matter of pushing the interface firmly on to the CPC's printer port. In the process most of the interface neatly disappears inside the CPC's case, leaving the new connector sticking out about 1.5cm further than the original.
No software is supplied. The programs needed to initialise it are very short - three single sided A4 sheets of instructions are provided, which include the required program listings.
For use under Amsdos the program consists of only five or six lines of Basic. They can be typed in and saved as a separate program, or can be incorporated into the Basic loaders used by many programs so that the port is automatically initialised when the software is run.
Another procedure is needed for use under CP/M, and this differs for CP/M 2.2 and CP/M Plus. In both cases the procedure modifies the CP/M program fiie so that when the operating system is loaded, the port is automatically initialised.
Note that it is important that the modifications are only carried out on a copy of the CP/M system discs, not on the originals.
The CP/M 2.2 modification consists of a 40 line Basic program run from Amsdos. It prompts you to insert the system disc and carries out the needed modifications. With CP/M Plus you have to make use of the SID program supplied on one of the system discs. In both cases the programs and instructions are clearly printed and described.
This Mk 2 version answers the criticisms of the earlier version - it does not mess up printing in programs that do not make use of it as long as it has not been initialised. If you make the small amount of effort needed to set your programs up so that the port is automatically initialised, you can largely forget about it and just benefit from the features it provides.
A number of programs will work with the normal printer port, and have the option to make full use of an 8 bit port if available. One such is Qualitas Plus from Seven Stars Publishing (06284 34451, which provides two complete sets of fonts.
The font for use with the standard port provides good character shapes within the limitations imposed, but it is not possible to have true descenders, and underlining tends to be pushed hard up to the bottom of the letters. The Qualitas Plus 8 bit fonts provide improved character shapes and better underlining.
Another program making use of the interface comes from KDS Electronics. Called Screen Master and described as a poster and document creator, it can be configured for use with or without an 8 bit port.
I was able to to define my own characters using either the CPC or CP/M Plus versions of Protext, making full use of my printer's facilities for the first time. The port will work equally well with any other program that allows you to redefine characters. Using the interface it is possible to print any character that can be defined within the matrix permitted by your printer.
The port also allows you to access any character that your printer is capable of printing just by sending the appropriate Ascii value. This can be done from your own Basic programs or, in many cases, from within other programs. If your printer has an IBM mode you will be able to use all the extra accented characters and line drawing characters.
If you have ever felt restricted by the limitations of the 7 bit port, or you have software that would benefit from it, then the KDS 8 bit printer port interface will solve your problems.