ICD P:R: Connection

Reviewed by John S Davison


Issue 30

Nov/Dec 87

Next Article >>

<< Prev Article



John S Davison tests a replacement for the 850 interface from Frontier Software at 69.95

The Right Connection?

If, like me, you've always cursed Atari for not providing the 8-bit machines with standard serial and parallel interfaces, then you'll be interested in the P:R:Connection from ICD Inc. of Rockford, Illinois. Using this device you'll be able to connect to standard (non-Atari) printers, modems, other computers, or any other peripheral device requiring a 'Centronics' type parallel or RS-232 serial interface.

Until now the only way to get hold of this product was to import one directly yourself, although Silica Shop did advertise it a while back. I've just heard that Frontier Software have become the UK distributor for ICD products, and can supply the P:R:Connection (PRC) along with many other interesting ICD 8-bit accessories. The review model came in via the import route, and this gave rise to a disastrous problem I'll describe later.

The package as supplied includes the interface box itself, a detailed instruction manual, and a double sided disk containing mainly communications software. No device cables are provided you have to supply these yourself.

ICD intend the PRC to be a straight replacement for the expensive and elusive Atari 850 interface. It's virtually 100%, compatible, including use of the 850 cables. In the few instances where there are compatibility issues, these may be fixed by using a supplied 'translator' program.


Finding suitable, reasonably priced device cables was a problem. I had several quotes for 850 cables at around 20 and over (EACH!), which I think is appalling. How can companies justify charging such horrendous prices for cables? ICD sell them for half this in the USA, so why can't UK companies manage something similar? Frontier Software could generate a lot of goodwill (with me, at least!) if they sold ICD cables too. (Frontier are now handling these cables at a reasonable price. Ed.) I eventually found some at a more acceptable price at York Computer Centre.


The PRC itself is a small plastic box measuring about 5" x 3.5" x 1" with a standard Atari serial bus cable emerging from one side. This plugs into the Atari's serial socket, and you then plug the rest of your I/O daisy chain into the serial bus socket on the PRC. There's no separate power supply needed (yippee!) as the PRC draws its power directly from the computer via the serial bus connection. It works fine unless you happen to own a 1200XL. This needs a simple hardware modification for which instructions are provided.

On the opposite side of the case are the I/O ports one parallel and two serial. "P1:" is the 'Centronics' parallel printer port, using a DB15 socket. "RI:" and "R2:" are both RS-232 serial ports, using DB9 sockets. The former is a full serial port containing all the handshaking lines required by certain modems, while the latter is a cut down version handling only receive and transmit lines. The old Atari 850 interface had two additional ports, one of which provided the rarely used 'current loop' facility. They were omitted from the PRC in order to keep down costs.

Inside the grey case is a very neat circuit board containing a number of discrete components and several IC chips. One of these is a complete microprocessor in its own right, containing ROM, RAM, PIA, and a CPU! The board also contains two jumper switches. One can be set to provide auto-linefeeds for your printer useful if you swap the printer between 8-bit and ST machines, as it removes the need to fiddle with those annoying printer DIP switches. The other switch allows you to turn the printer function off, again useful if you're already using a directly connected Atari printer.


My first test involved replacing the trusty Blackthorn interface I use to drive my Star SG10 printer. It took just a few moments to connect up the PRC in its place and to try a few quick LPRINT commands from BASIC. Result Error 143. Hmmm, not so good. I rechecked all cable connections and retried it. Same result. I tried to LIST a BASIC program instead. No good. I tried to print a document with Atariwriter Plus. Still nothing. No amount of experimentation would induce it to print. Disaster!

At the time I wasn't aware that Frontier Software were about to start handling ICD products, so I contacted Silica Shop who kindly offered to help me sort out the problem. I took the PRC and cables down to them and we tried substituting different cables, computers, and their last remaining PRC. Surprisingly, even this didn't work. (Thanks anyway, fellas!)

Baffled and disappointed, I went home and wrote to ICD in the USA. A few days later I received a phone call from ICD president Tom Harker, who explained that the first few thousand PRC's made were incompatible with PAL system 8-bit machines (i.e. those used in the UK). The design was subsequently modified to fix this, so my PRC (and Silica's?) must have been an early model. The solution was to replace the 4 MHz crystal on the PRC's board with one of 3.9 MHz. I received a replacement crystal from him by airmail shortly after, and fitting this caused the PRC to drive my printer exactly as the Blackthorn had. Moral if you import your own hardware from the USA make sure you know what you're getting!


When used to drive a parallel printer no additional software is required simply plug in the PRC and go. Using the RS-232 interface is rather more complex, needing some form of driving software. This is where the ICD supplied disk comes in, as it contains a number of useful programs.

There are three (yes, three) different communications programs provided. All are public domain programs and widely used in the USA. The first is AMODEM 7.2, considered by ICD to be one of the best communications programs available for the 8-bit machines. Then there's my favourite 850 Express, a modified version of 1030 Express, which is immensely popular in the USA. Just looking at it I can see why it's got some superb features! Finally, there's RSCOPE, needed only if you're rich enough to afford to access and download programs from the USA's CompuServe system.

There's no separate documentation provided for this software it's all on the disk, so you can either print it out or view it directly on the screen via a text editor.

I haven't had a chance to try out the communications side of the PRC and its software yet, so I'll defer comment on it until the next issue. Watch this space for details.

ICD's P:R:Connection is great news for 8-bit users. At last you can be freed from the straightjacket of Atari specific printers and choose virtually any one that takes your fancy (modems too!). Considering you also get a diskful of useful software it's superb value for money. If you need a good, comprehensive interface device for your 8-bit machine, then look no further. Get ICD's P:R:Connection,