Fairlight-CMI

Hi Hans.

Congratualtions, I had also considered buying this fairlight on ebay.

Because I was considering the purchase and knew the lightpen was not
included, I did some research on the subject.

Greg Holmes kindly informed me that the pen on his system is as follows:

Information Control Corp.
LP-660-T-LL-AL-R
P/N41004546-022
S/N80L1353
U.S. Pat.3475612


A quick google patents search revealed this:

http://www.google.com/patents?vid=USPAT3475612&id=FoxjAAAAEBAJ&dq=3475612

Googling for "Information Control Corp" lead me to  a list of
companies who manufacture light pens (link below)

http://www.billbuxton.com/InputSources.html#anchor682875

I placed a call to what I thought was "Information Control Corp" in
Connecticut, NY. However, the people there told me that the company
"Information Control Corp"  had been sold to someone in California. I
had a California number for them but it seems to have been
disconnected and my search for a direct replacement ended there.

However, there are many types of light pen manufactured today. It
seems the basic principle is still the same as that of the light pen
used with the fairlight. The link below provides a simple outline of
this principle.

http://www.inkwellsystems.com/technical.htm

I found a CMI IIX service manual online and according to that: 

"The light pen operates by sending a pulse back to the computer when
the phosphor dot is `seen' to flash past. The light Pen Interface
Q-219, located in the Mainframe generates X-Y co-rdinates from the
timing of this pulse. As well as this `Hit' signal from the lightpen
there is a `Touch' signal which indicates that the operator has
activated the pen by touching the tip. For detailed information, refer
to the GRAPHICS TERMINAL SERVICE MANUAL."

As you will see from reading the info at the link above, this seems to
be the same principle used in current light pens. Whether you will be
able to get one to talk to the fairlight is just a guess from me at
this point but it is my feeling that it might be possible for a modern
light pen to be re-purposed for use with a fairlight if it was
supplied with a circuit/wiring diagram.

I couldn't really sacrifice the time to time to repairing this
fairlight due to other projects/commitments and figured I would wait
until another one comes along (yes, I know that could be a long time!)
but I wish you the best of luck with replacing the pen, I would be
really interested to know how things work out so please keep us all
informed!

Best,

Donnacha Costello,
Dublin,
Ireland.