1991 – 1992

VAX-SIMILE was the name of a set of applications that allowed users of DEC (Digital Equipment Corporation) VAX terminals to send faxes from their desks by directing their documents to a special printer. In reality, that printer was a PC with a Fax card queuing and sending faxes to recipients specified by embedded tags in the text.

The VAX 8550 and 8350 at my old office

The VAX 8550 and 8350 at my old office

The tags also allowed the users to specify lists of recipients, preferred delivery times, and priorities.

In 1993 it was not unusual to see people lined up at the fax machine waiting for their turn. My company was no exception, and so the idea for an automated system was born.

PCs were also quite scarce, and most of the employees were using simple terminals. I found a fax card and an old PC, and started tinkering with them.

The fax card APIs were quite crude (and unsupported), but did provide the basic functionality I needed.


Design and Development

I decided to use the VAX/VMS print queue by replacing the printer with a PC. Users were already familiar with the VMS printing procedures.

The PC would receive the documents through the RS232 serial interface, parse and strip the embedded fax instructions added by the user, save the document, and schedule the delivery.

A VAX/VMS application was communicating with the PC through a socket interface to maintain a list of the faxes status, so the users could monitor and check the delivery outcome.

A small army of corollary tools was also created to manage the process, especially on the VAX side. Some of them had to be developed in the VAX Assembler language. Fortunately, it was very similar to the Motorola 68000 one, which I studied a bit while I was working with Commodore Amiga computers.




  • Ability to send faxes to multiple recipients with a single submission
  • Fax scheduling for evenings or nights for cheaper rates
  • Users accessible VMS application to monitor and check the fax queue status
  • Complete printed documentation with User, Configuration, and Technical manuals



After I left the company and started working for Microsoft, the software kept working with no issues for about a year. I was then called back during a brief vacation in Italy when the company bought a brand new VAX system based on a new RISC architecture. All I had to do was to recompile the VAX portion of the application and everything was working again in less than a day.


  1992 /  Last Updated May 16, 2013 by Roberto Ziche