Not current and not DOS... but years ago, around 2011, I helped set up a series of QEMU emulators running DEC Ultrix and MIPS Unix software that called out and retrieved data from weather stations only reachable by modem. The software had been written years prior in C and nobody had the source.

The box running the QEMU emulators had a bunch of old US Robotics modems hanging off it via USB serial dongles.