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History
When the Z88 came out there was no internet or standard for communicating between different computers. The key strength of the Z88 has been its ability to share its data with a range of computers. Cambridge Computer released PC Link, PC Link II, BBC Link, and Mac Link.
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Third party software were provided for the PCW, Amiga, Archimedes, Atari ST & QL Link.
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For more info on Sector Software click here |
Computers and methods of communicating have changed since then, the Serial Port has given way to USB and even Bluetooth. The Z88 keeps up to date with thanks to its band of technical users
Making a good computer link for the Z88 need to address the following:-
- Faster Serial Port - OZ v3.0 slow implementation of the Serial Port - this is limited to 1200 baud.
- Protocol - it needs to be able to send binary and ascii files.
- File conversion software - PipeDream file structure is unique.
Protocols
To get data across to different computers a known protocol was needed for the Z88 so that it could be used with another computer using the same file protocol.
Z-Modem
Wordmongers produced Z-Term which was designed to work with Hayes MODEMs. Z-Modem allowed files to be sent and received to Bulletin Boards.
XY-Modem
Dennis Gröning wrote this application. It runs the Serial Port at the fastest speed possible.
XY-Modem popdown application for the Z88. Version 1.1, 26 December 1999.
Computer Links
Tx, - File Transfer System used a propriety protocol and was developed for over 100 different micros which included the Z88 and the PC. It included a PipeDream to WordStar conversion utility.
Cambridge Computer initially used the Z88.s Imp-Exp protocol for their BBC and PC Link. This meant giving commands from both the Z88 and the other computer before the file transfer could take place.
PC Link II was supplied as two programs, one ran as an application supplied on a 32K EPROM card (written by Colton Software) and the other on a disk as a DOS program on the PC. This introduced a new protocol with new commands that enabled all the commands to be controlled from the PC and later with the Mac.
Ranger came up with a different approach. Rather than controlling the software from the PC, they used the Z88 itself. They had already written software using a subset of the Christie tape protocol to run on the Z88 using the serial port for their Ranger Disk Drive. A few tweaks were needed on the Z88 and a small DOS program developed for the PC to use either COM.1 or 2 that looked like the drive from the Z88 and they were off. Their program on the Z88 ran outside of OZ controlling the serial port directly, enabling faster transfer speeds to be realised. The DOS program written, used the processor clock to set the speed of the serial port and was designed to run on a 486 computer without the turbo switch on. As processor speeds increased, this program began to fail. Dennis Gröning rewrote this software using a different method of timing and offered all the COM ports to be selected so the program could be continued to be used with faster machines.
There was no reason why this small program was not developed to run on other computers i.e. Apple Mac, but this was not to be.
Gunther Strube wrote Eazylink, improved the PC Link II protocol, speeded up the serial port and added new commands.
Rastersoft Z88Transfer can use IMP/EXP, PCLINK or EAZYLINK protocols. When the author tried this last, it would not transfer binary files. This has been documented as fixed. I need to test it again.
Eazylink 2 supports three O/S. For further information Click Here.
File Conversion
PipeDream to WordStar and PipeDream to Lotus 1-2-3 for the PC
PipeDream for the MAC.
The BBC Computer had View Professional which used the same file structure as PipeDream.
How do they all stack up?
Z88 Applications using different Protocols | |||||
| Manufacturer / Developer | Program | O/S | Faster S-Port | Protocol | File Conversion |
|---|---|---|---|---|---|
| Z-Modem | OZ | |||
Dennis Gröning | XY-Modem | OZ | |||
| Dennis Gröning | ChristieRangerlink | ||||
Z88 Transfer Programs with other Computers | |||||
| Manufacturer | Program Including | O/S | Faster S-Port | Protocol | File Conversion |
| Tx - File Transfer System | ||||
| BBC Link | BBC | |||
| PC Link | ||||
 | Eazylink2 Imp/Exp |  |  |  | |
| PC Link II | ||||
 | PC Link II Z88 Link | 16 bit | | | |
Paul Robson | 16 bit | | | | |
| MAC Link | ||||
| Ranger Link | ||||
| Eazylink | 16 bit | |||
| Z88Transfer | |||||
| Eazylink 2 | |||||
| Eazylink 2 | |||||
| Eazylink 2 | |||||
Z88 Serial Cable
None of the above Computer Links will work without a Cable. At the time that the Z88 was designed there was no standard connector, so Cambridge made up its own. It uses the 9 way 'D' type connector which are used with the modern computers, but they are different in two different ways.
- Mechanically - they do not have the stand-offs to accept the screw down connectors. This means that if a normal computer cable is used, it will not fit completely in the Z88 as the screws on the cable connector will prevent in from plugging into the Z88.
The Z88 Serial Cable connector do not have any screws fitted, so it fits into the Z88 perfectly. So why not just remove the screws you may ask?
- Electrically - The bad news that even the connections to the nine pins are different.
There is a lot of misinformation on the net about making your own cables, this is because initially the connection may work by sending a few characters across the link, this breaks down if handshaking is not respected. Before blaming the software, please get the correct cable, then any of the transfer programs may be used confidently.
9 way Cable with screws
