Barry Miles hooks up his 64 to an intelligent printer interface

The Connection is an intelligent printer interface for the Commodore 64 and Vic 20. It allows both of these machines, with their strange character sets, to be used with virtually any dot-matrix printer giving full Commodore compatibility. At the moment, it is only available from the US.

The Connection comes in an attractively labelled box with three plugs leading off it. The DIN cable goes into the 64 or disk drive's serial socket and a conventional Centronics plug connects to the printer. The third cable plugs into the cassette port to obtain a five volt power supply for the system. Fortunately, this plug has an extension coming out of the back for the cassette connector, so there is no problem using both the Connection and the tape unit.

Levering up one corner of the top cover reveals two DIP switches. These are not mentioned in the manual so a little experiementation was required to figure out what they did. One of these alters the number of line feeds to the printer after a carriage return. The other one doesn't seem to do anything in particular.

Accompanying the Connection is a five chapter booklet containing all the necessary information to enable you to get the interface up and running. As usual with US products, the tutorial and installation sections are written in a chatty, informal style.

The reference section is slightly confusing because it tries to deal with too many printers at once.

The main features of the Connection are its emulation ability and the fact that it can be configured to suit your printer. The manufacturer is quite willing to supply a different ROM when you change your printer, so you can be sure of getting the maximum benefit from the device.

The interface really comes into its own when you take advantage of its special capabilities. For instance, it is possible to indent printing by a number of characters, change the width of the printing and print Commodore graphics characters.

Numerical work is eased with the tabbing capabilities. Simply precede the data to be tabbed with CHR$(16) followed by a two digit number specifying the number of tabulation spaces counted from the left margin. You can define your own graphics symbols and you can even tab the print head across by individual dot increments.

The Graphic repeat function, together with the dot tabulation function, can be used to give a very powerful graph plotting facility. Sending special codes to the printer is covered by sending two escape codes followed by the character code. These will be transferred directly to the printer without any modification by the interface.

There are six modes of operation:

• Ready, indicated by the ready LED, shows that the interface is ready to receive data from the computer.
• Wait (wait LED lit) occurs when the interface is waiting for something to happen, on the printer side, and will not accept any more data until something does. There is a buffer within the Connection with nearly 2K capacity, and when this fills up, the interface goes into wait mode until the buffer has enough space in it for more data. The reset button can be used to empty the buffer and return you to ready mode, but all the data is lost.
• Print Test mode is invoked by pressing RESET when the interface is in ready mode. When the ready lamp starts blinking, the reset button should be pushed again and the test begins. This consists of printing a full page of characters confirming the correct functioning of both the printer and the interface.
• Emulation mode allows you to turn your printer into a Commodore 1515 or 1525, if your interface has been correctly matched to your printer. This matching is made necessary by various technicalities such as graphics characters, etc.
• Total Text mode enables the printer to emulate a Commodore printer, except that no graphics symbols are printed. Substitutions are made instead and, in some instances, these may be of more use than the real graphics characters. Cursor movement and colour assignment symbols are printed as three characters which describe the function - HOM is home, GRN is green, and so on. The other graphics symbols are printed as a number representing the CRH$ (CBMCII) code number associated with the symbol.
• Transparent mode allows information to be sent without any interpretation at all, and codes are sent directly to the printer.

Additional commands are available from the Connection itself, to make the printer more usable. The unit can be given a different device number from the usual No 4. The Fold command can be used to improve the readability of program listings by starting a new line when a colon or space is encountered within ten columns of the width limit. Status can be used to retrieve information about the current parameters and general well-being of the interface.

The Connection is an extremely attractive device which will improve the versatility of your printer and save frustration if you buy software which is peculiar to Commodore printers. For $119 it is not cheap, especially when the carriage, duty and VAT have been added.

However, it is easy and convenient to use. For some people, this may be more important than spending the extra cash.