I seem to recall that there where at least 2 different external floppy connectors.
There is the one that can still be found on current docks and port replicators, and then there was another older one.
In addition some ThinkPads support a floppy drive on the parallel port, using a special cable
--Tonko 16:46, 8 February 2006 (CET)
My T23 doesn't have a floppy connector, but my 770 does.
beware identical Toshiba
Toshiba used a same connector as IBM (17 mm 26 pin). Like ThinkPad parts, they are abundant in secondhand market. I wonder if they are compatible; I did not test, myself. I found only one user report (IBM floppy with Toshiba PC), and that user reports failure, not compatible. How unfortunate, IBM and Toshiba did not choose identical wiring plan.