We still have them: our first modems. The very first one was a 2400 baud BEST modem connecting us via UUCP to Karlsruhe. In October 1993, we were among the first 10 Xlink PoPs.
The modems here are rock-solid USR Courier modems. We are using them still as emergency dialins in case the main dial-in machinery should fail. With these modems, I can even use a trusty DEC VT-320 at home. It will give me directly a Unix login, without any TCP/IP needed. We have half a dozen modems distributed all over the place. One or two are used to send faxes.
Note the cute 2x2s between the Couriers. We had a dead one due to overheating one day when they where still stacked closely. Nowadays, modems (at the ISP side) are DSP-based modules that are inserted into an access router. A simple module easily implements 16 modems -- in a third of the size of a single modem you see here.
Times, they are a-changing. USR ain't USR anymore, and, not suprisingly, Xlink ain't Xlink.