These cables are known good.
http://tandy.wiki/Model_T_Serial_Cable
And the blurb at the top explains why the 100 is weird and what you need
and why any other cable you got is probably wrong, and what adapter to
get if you want to use that cable anyway.
There are actually one-piece usb cables but as a personal preference I
don't recommend them because that kind of adapter is essentially "wrong"
for every other serial usage in the world. You would need either a
null-modem adapter and/or a gender-changer adapter to make it work with
anything else but a 100. Also the single piece usb cables I think are
only hand made ones on ebay. There might be real factory ones but super
rare. In fact the few I've seen were actually just mis-labeled and were
actually parallel ports. I'm not sure I've ever seen one other than home
made.
I'd rather have a usb-serial adapter that was standard, providing a
standard port, exactly the same as what was on the back of old
motherboards for about 30 years, and have the special wiring just be in
the serial cable. Those kinds of cables are uncommon, but are still more
common than a usb-DCE-female cable. As you see above I found several off
the shelf factory cables. Some with full handshaking (real flow control)
and some more with only 3 wires plus the dtr/dsr loopbacks (fake flow
control) already in the ends.
Just my suggestion.
On 1/18/26 12:51, Erik van der Tier wrote:
Hi,
I’ve been trying to get my T102 to talk to my modern MacBook. For this
I’ve bought a usb-c to db9 cable and a db9 to db25 serial null modem
cable. I have today installed a REX# in my t102 as well.
Anyway, I haven’t been able to get a connection to a terminal program
nor TS-DOS. I know this *can* work on a Mac as I”ve previously had a
T102 and a pretty crazy franken-cable that work like a charm.
This time I though, I’d get a simpler setup with only one usb-c to
serial and a null modem cable, in stead of a USB-A to serial, a DB9
serial modem cable, a null modem converter and a DB9 to DB25 converter.
Crazily enough that horrible mess of cable and multiple adapters worked.
The serial cable that I got this time around is this one: https://
www.amazon.nl/Vrouwelijk-parallelle-printerkabel-Datatransmissie-
Communicatie/dp/B08C9TXXCK/ref=sr_1_18?
__mk_nl_NL=%C3%85M%C3%85%C5%BD%C3%95%C3%91&crid=TRBHXQVKSIVH&dib=eyJ2IjoiMSJ9.NOI_htfBsniWi16cA7NrpAsbwAFQHVL9HsjtCZDB-QrcH328-7sC_CZHghnU9G19bemEAqjGO2AYpuVod7RPWDwXiMs-6romUKb81fCynFFx7v8y0LYEfR77WCc9mMFZOu_J2ZEZXMmzgzG4UVOAP2-9q0vmmPaW_Ko3ivHRWYh5ZifAD_7KLGEqK7aFxOn22KcARopde7vuFHpTzbvko1rPviFqUyTirH8GS7y8mj4GWrIXFhwTAiFCo6ZOaSuwTLUTNk1apT1lg5p8hgHYLzKCiN7PfDL-dWWzZUZDUfE.wnq2KLE6yCDlC49ZLZqqn82UL8RLijAKlOy-veK9Jtk&dib_tag=se&keywords=Tripp+Lite+Model+P456-006+6+ft.+Null+Modem+DB9F+to+DB25M&qid=1768668965&sprefix=tripp+lite+model+p456-006+6+ft.+null+modem+db9f+to+db25m%2Caps%2C113&sr=8-18 <https://www.amazon.nl/Vrouwelijk-parallelle-printerkabel-Datatransmissie-Communicatie/dp/B08C9TXXCK/ref=sr_1_18?__mk_nl_NL=%C3%85M%C3%85%C5%BD%C3%95%C3%91&crid=TRBHXQVKSIVH&dib=eyJ2IjoiMSJ9.NOI_htfBsniWi16cA7NrpAsbwAFQHVL9HsjtCZDB-QrcH328-7sC_CZHghnU9G19bemEAqjGO2AYpuVod7RPWDwXiMs-6romUKb81fCynFFx7v8y0LYEfR77WCc9mMFZOu_J2ZEZXMmzgzG4UVOAP2-9q0vmmPaW_Ko3ivHRWYh5ZifAD_7KLGEqK7aFxOn22KcARopde7vuFHpTzbvko1rPviFqUyTirH8GS7y8mj4GWrIXFhwTAiFCo6ZOaSuwTLUTNk1apT1lg5p8hgHYLzKCiN7PfDL-dWWzZUZDUfE.wnq2KLE6yCDlC49ZLZqqn82UL8RLijAKlOy-veK9Jtk&dib_tag=se&keywords=Tripp+Lite+Model+P456-006+6+ft.+Null+Modem+DB9F+to+DB25M&qid=1768668965&sprefix=tripp+lite+model+p456-006+6+ft.+null+modem+db9f+to+db25m%2Caps%2C113&sr=8-18>.
I don’t really know much about serial cables and connections, so I’m
having a hard time debugging this setup. Does anyone of you have an idea
of what’s wrong, or what serial null modem cable that can be ordered in
Europe and is know to work?
Cheers,
Erik
--
bkw
