TL;DR: I complain about my failings and show off pictures and log files. Later some gradual understanding of ISDN and why this probably won’t work with my particular version of the Courier I-modem with a U interface. Turns out U is electronically incompatible with S/T. In my telcom fiddlings to get a 56k dial-up modem […]
Tag Archive 'modem'
TL;DR: replaced LH1056 solid state relay / optocoupler at U3 One of the USR Courier HST modems I purchased recently had a peculiar problem that if I plugged the phone line into the “wall” jack of the modem it returned NO DIALTONE when I tried to dial something, yet I was able to dial something […]
US Robotics Courier I-Modem power adapter substitute
Posted in retro on Apr 29th, 2025
TL;DR: Original US Robotics I-modem power adapter is extremely rare. I cut mine open to document it. Original adapter provides 20 V AC (1500 mA capacity) across pins 3-4 of mini-DIN connector, no other voltages. Substituting a $15 24 V DC power adapter seems to work just fine. The US Robotics Courier I-Modem seems to […]
US Robotics Courier 14400 HST power adapter update
Posted in vintage on Apr 16th, 2025
After proving my HST worked in my previous post with an ATX power supply, I went looking for triple-output power adapters (5 VDC, 12 VDC, -12 VDC). I finally found something that works, an ELPAC WM113TT AC-DC power adapter along with a new female DIN 5 connector. There were a few power supply ideas […]
US Robotics Courier HST power adapters
Posted in Uncategorized on Apr 9th, 2025
I picked up a couple of “widebody” USR Courier HST modems and have been working through documenting power adapters for them and sorting out what goes with what. I figured out almost all Courier and HST models have different power supplies and voltage requirements. I’ve been tracking down manuals and cross-referencing the FCC IDs in […]
What happened between the Zoom VFX and Telebit TeleBlazer?
Posted in retro on Sep 3rd, 2024
Around 1995 I had a Zoom VFX V.32bis 14.4k modem as my main workhorse. It was a white plastic shell with a smoky brown translucent front face. I decided to buy one recently for old times sake: I also came into possession of a Telebit Netblazer PN (which I need to finish working on and […]
