While devices and machines with clock cycles to spare have evolved to harness increasingly-complex network protocols, especially the widespread IEEE 802.3 (Ethernet) and IEEE 802.11 (WiFi) families of specifications, less-powerful devices have historically engaged in only limited two-unit communication. A particularly unfortunate example is TI graphing calculators. This ubiquitous, relatively-inexpensive computing platform is owned by millions of high-school and college-aged students around the world, but only natively supports a two-unit transfer mechanism. Built around a z80 microprocessor executing at 6MHz or 15MHz, it is incapable of participating in modern networks, but has sufficient computation power to support a robust network tailored to its strengths and weaknesses. cnfull presents such a protocol, boasting point-to-point and point-to-multipoint communication, asynchronous tranceptions, failure resistance, robustness against noisy channels, and many other features of a reliable and extensible network protocol. The implementation is small, fitting into under 1KB of z80 assembly code, and is shown to perform with superior reliability and at comparable speeds than even existing two-unit transfer protocols.