The Tinyserial library is a space-saving alternative to the Arduino software distribution's libraries for reading and writing characters and strings to the USART0 serial port on the Atmel ATmega168 and ATmega328p MCUs found on Arduino Diecimilla and Duemilanove boards. While the Arduino software distribution's libraries provide interrupt-driven serial I/O with far more features and support more MCUs, the Tinyserial library provides only the most basic polling-based serial I/O. However, the Tinyserial library uses far less Flash and SRAM, thereby giving you room to implement larger and more complicated applications on your boards. The Tinyserial library respects the GNU libc ABI, so you can call into it from C and C++ programs.
Qodem is a re-implementation of the Qmodem DOS shareware communications package, updated for more modern uses. Major features include Unicode support, scrollback buffer, capture file, screen dump, dialing directory, keyboard macros, script support, Xmodem, Ymodem, Zmodem, and Kermit. It can connect over serial port, telnet, ssh, rlogin, and command line, and supports multiple terminal emulations including ANSI.SYS, Avatar, VT100/102, VT220, and Linux.