IBM 3101-12 ASCII terminal - need fuse holder

Paul Berger phb.hfx at
Fri Jan 29 12:19:23 CST 2016

On 2016-01-29 12:28 AM, Ethan Dicks wrote:
> Hello, all,
> I was just gifted with an IBM 3101-12 ASCII terminal that happens to
> be missing the fuse and fuse holder.  Unlike a lot of 1960s and 1970s
> gear, it's not round.  It's square.  Is this a standard IBM thing from
> the 70s/80s?  Anyone know where I could get one?  It seems to snap in
> and probably fell out at some point under its previous owner.
> Also, I found only a little info on it from Googling.  Later IBM ASCII
> terminals emulated ANSI command or Wyse-50 or something.  I couldn't
> find anything on the 3101.  Is it a glass TTY or does it respond to
> any cursor positioning, etc. commands?
> Thanks for any tips and info.  Worst case, I can bodge in a fuse on
> the inside, but if I can find a replacement holder, I'd like that
> more.
> Thanks,
> -ethan
I did a quick google search for 'ibm 3101' and among the hits was a 
manual on, there are two 
manuals one of which is the "Terminal Description" that seems to have 
plenty of information about the data stream.

The protocol is unusual at least the mod 12 is one of the character mode 
terminals supports RS/232 and current loop.  The weak point is the 
keyboard, the key modules have a leaf spring in them that flexes every 
time you press a key and they break.  The good news is almost every IBM 
keyboard from that time uses exactly the same key module so spares may 
not be hard to come by.  When I was servicing machine with this type of 
keyboard more than 30 years ago, I carried a dozen spare key modules in 
my trunk all the time.


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