Microfax Modems

The Microfax pocket modem was a wonderful portable fax.

Microfax used to make a pocket modem, about the size of a cigarette package (106mm x 57mm x 17mm, weighing 150 grams). What was neat, especially for palmtop users, is that the modem had a few more smarts available in it than average. The Z80 derivative that runs it knew how to work independent of fax software in your computer, so you could send (and in some circumstances, receive) a fax without owning any fax software. The Microfax modem originally came with a version of Delrina WinFax software, so if you run a old Windows PC, you can use that software. Any Class 2 Fax software should work.

This is a very old modem, so it only runs CCITT V.22bis, V.22, V.21 and USA Bell 212A and 103 standards. That is, 2400 baud is as fast as it goes (except for Fax). Many modern modems and ISPs do not reliably drop back to these speeds.

The Microfax normally works off a small wall wart plug pack transformer. You could buy an optional battery pack which will run it for about 24 hours off four AA penlight batteries (less time if it is in heavy use). The battery pack plugs into the same DC socket as the power plug connector.


The RS232 serial port uses TxD, RxD, Ground and DSR. I don't think it uses any other lines. Set your serial port to 9600,8,N,1.

The parallel printer port assumes it has the full set of connections, so ensure your cable supports them all.

1 /strobe
2 data 0
9 data 7
10 /ack
11 busy
12 paper
13 select
15 /fault (32)
17 /ready (36)
18 aux1 (33)
19-25 ground

Activity Mode Light

When first powered up, the activity LED will stay on for a few seconds while MicroFax tests its internal circuits. On successful completion, you should hear a short burst of sound, and the LED will blink on every four seconds.

The MicroFax when idle will blink the LED on every four seconds. When Active, it will blink fast. When handling a message, the LED will be on, and blink off every four seconds.

There is an LED beside the phone socket. This indicates when MicroFax is sending or receiving online.

Pushbutton Control

You can use the small pushbutton on the side of the MicroFax.

One short press. Go online and receive fax. Use if you pick up the phone and hear a fax machine.

Two short presses. Alternate between LaserJet and InkJet printer modes. Overrides automatic recognition. Low double beep means LaserJet, high double beep means InkJet.

Three short presses. Answer phone on third ring. Four for fourth, etc.

One long press for three seconds or more. Reset Microfax. You will hear beeps as it resets.

Print Instructions Using Microfax

You can print the Microfax instructions by connecting your Microfax to the parallel printer port. Power up printer. Then power up Microfax. It will print out a set of instructions, if the printer is compatible with it. Your printer must be compatible with either a Hewlett Packard LaserJet+, or with an IBM ProPrinter, or be able to fake it. WinPrinters obviously won't work. Some printers prevent the MicroFax from printing its instructions. Remember, printer powered up first, then power up MicroFax so it can attempt to detect the printer.

Fax Text Send without Computer Software

To send a fax, use any text editor to make an ASCII text file, in which the first word is fax, and the first number is the fax number. Send that to the Microfax via your serial port at 9600,8,N,1. The Microfax will format, and send your fax. No special software, no high powered computer.

Fax Receive

When the Microfax receives a fax, it questions the computer to which it is attached via the serial line for compatible fax software.

If it fails to find fax software, it checks its own standard parallel printer port for a printer. If it finds a printer, it attempts to determine whether it is a HP LaserJet compatible, or a dot matrix or bubble jet. If an ink jet, it formats fax as Alternative Graphics Mode. On older Cannon Bubble Jet, you need to select this mode using DIP switch 7. It may not be available on recent printers. MicroFax formats the fax and prints the fax. On older printers, this can take several minutes.

Store Fax

If MicroFax fails to find either a computer or printer, it stores the fax in its own 512k internal ram (space for say 15 pages) until such time as it has a computer or printer attached. This means you can take it when you travel, and receive faxes in your hotel room, without having to leave the computer there and switched on.

Redirect Fax

You can remotely command MicroFax to send a stored fax to another number. Using a tone phone, dail the phone line to which the MicroFax is connected. It should answer with a three second high pitch tone. Dial password (default is 11). Dial #, followed by the number to which the fax should be redirected, followed by another # MicroFax will send a burst of pips, and hang up. It will try the number five times. If additional faxes are received, it will send them also.

To cancel redirect dial 11 (default password), then 00. All messages will be cleared.

Use these commands from a fax machine to collect your faxes.

Change Password

Dial MicroFax, send 11 (if password is still default), then send ##xx## where xx is the two digit password you wish to use.

Other dial up commands are * (answer as fax), # (answer as modem), of after password (default 11), 00 (reset), # (start or end redirect), ## (start or end password change)

Modem Use

The Microfax also works fine as a regular, albeit slow, modem. I used some old fashioned free software like Kermit to run it, using standard Hayes AT commands entered manually. Never seemed to give any problems with this. You should note that Windows computers do not seem very compatible with software like Kermit. I haven't experimented with HyperTerm.

AT Command Set

These are the commands used by the MicroFax. * indicates default.

A answer
A/ redo previous command
B0 1200bps CCITT V.22 *
B1 1200bps Bell 212A
D dial number (also uses T tone P pulse , pause 2 seconds
E0 No echo
E1 Echo command characters *
H0 Hang Up
H1 On line (off hook)
I0 Request product ID
I1 Report checksum
I2 Test memory (OK or error)
I3 Report software version
I4 Report product name
L1 Speaker low
L2 Speaker mod
L3 Speaker high
M0 Disable speaker
M1 Speaker off during message
M2 Speaker on *
O0 Online
O1 Online and retrain
P Set pulse dial
Q0 Display result codes *
Q1 No result codes
Sr Set to Register r
Sr=n Set register r to value n
Sr? Display value in r
T Set tone dial *
V0 Send numeric result codes to PC
V1 Send codes as text to PC *
X0 Ignore dial and busy tones
X1 Ignore dial and busy tones
X2 Listen for dial, ignore busy
X3 Ignore dial, listen for busy
X4 Check dial and busy tones *
Z Reset
&F Factory defaults
&S0 DSR always on
&V Display active and default settings
+F Prefix for TR29 Class 2 command set
+FCLASS=2 Enter Class 2 fax modem mode
S Registers are
S0 Number of rings (default 2)
S6 Wait before blind dialling (default 2 seconds)
S7 Wait for carrier (default 30 seconds)
S10 Hang up after no carrier (14 x 1/10 second)
S12 Guard time before +++ (default 50 x 1/50 second)

Historic Notes on Microfax

I've bought each of my Microfax when I saw the inventor at the local annual PC show. The company seemed a small one, run by Michael Roberts and his wife. He does the design, and the modem appears to be built by outside companies. I've seen it sold in Australia by Dick Smith, and another Psion version is sold by Microfax in London. If you could talk to him during quiet times at the show, Michael Roberts was willing to tell you how to download your own Z80 code into the modem's address space, and have it jump to and execute your code. I have a little routine of his that makes the internal speaker play music, for example.

I missed the 1997 show because I was overseas, but in 1996 he was showing off his Synergy gadget. This is a telephone answering machine, fax and 28.8kbps modem in a very small package. It stores the voice messages independent of your computer, just like the original fax modem works independent. It uses 1 MB of Intel flash memory, and more can be added.

I found a note around September 1996 noting Microfax Modems Ltd, Conbar House, Mead Lane, Hertford, Hertfordshire SG13 7AS UK. Of course that is almost certainly now obsolete.

Unfortunately, Microfax are no longer in the online White Pages. I sort of suspect they went overseas, perhaps to the UK, but don't have any hard evidence of what happened to them. A real pity, as I wouldn't mind getting one of the Synergy variations.

On 18 June 1997, Phil Harvey (philh at gnhtrl.agw.bt.co.uk) emailed

"I don't know if this is any use but Microfax are supported in the UK by DIP Support (tel. +44 1483 202070, fax +44 1483 202023). The technical consultant is John Drinkwater. I don't know if they have an email account.

"I was interested to read that you like the Microfax. I have a 144 which I'm trying to use with PsiMail Internet and my Psion 3a. However I am having trouble setting it up for a dial-up PPP connection. The initialisation string probably requires fine tuning.

"I have a slower 3Fax modem which works fine compared with the Microfax - once I get it working, that is. Curiously, I did get it to work once but I don't know how!"

I also had email from a Western Australia bulk user saying the QC on the production models was such that many had to be returned with faults. No further information on what fault (mine still work fine).

I now have no evidence that the Microfax company exists any longer in Australia or the UK.

In May 2005 I got an email from Walter Wright, who says: I was just "tidying up" my burdgeoning address book (on my Psion S5), and I came across Mike & Susie Roberts of Microfax fame. I wondered if they were still around, so a quick Google revealed... well, your website actually. My connection with Mike was as the author of a Psion 3a package called FaxIt. It was a general purpose fax package which behaved quite like the Psion 3Fax product, but would work with most Class II fax modems. I got about 1500 registered users before fax was finally replaced by the interweb. There's still a support website (http://freespace.virgin.net/faxit.support), but I never get any support calls anymore, let alone registrations, hence I've let the website stagnate a bit. Oh yes, back to Mike. He was interested in some way of being able to view the faxes stored in the Microfax, and decided that as I had the Send side pretty much sewn up it would be very straightforward to build a receive and display module. He came to visit me in Sonning, (Berkshire, UK), on one of his trips to the UK, round about the time your article talks about. John Drinkwater came along too. Unfortunately, the comms protocol side of the Microfax was a bit flaky, and I never could get it to behave in a predictable manner. The project died eventually, as not long after, the S5 arrived with its free send and receive fax software built-in. I still have a Microfax somewhere.

I hope you have enjoyed www.ericlindsay.com.