Reliable Serial File Transport
Here is a small command-line tool for transporting small files (up to 1MB) over an unreliable serial link. Internally, it uses a flexible automatic repeat request (ARQ) protocol to maximize efficiency while guaranteeing reliable transfer over a serial link of unspecified reliability and latency. (It was originally used to transfer pictures between military radios.)
The application is lightweight (10KB) and has no dependencies (other than the standard serial port WIN32 API). See the readme for more details.