The most feature rich terminal program for the 4/a is TELCO.. This supports ANSI graphics (NO COLOR) and 40 and 80 column modes (80 column requires a 9938 or greater VDP and does not work currently with F18a 80 column mode) Multiple file transfer protocols, printer spooling etc..
This file contains a disk image, pdf format manual and keyboard overlay http://ftp.whtech.com/communications/Telco%20-%20Complete%20Package.zip
Other terminal programs and their features
Term80 – 80 column terminal on stock VDP, uses a TINY FONT but supports color ANSI and high baudrates using specialized rs232 routines and memory devices for buffering data.. buggy and incomplete but still pretty cool
MXT – Mass Transfer – allows for multiple file transfers and standard ascii terminal emulation , xmodem included as well this has also been ported to work as a telnet client for TIPI
Fast Term – ASCII terminal program that works up to about 19200 baud..
Terminal Emulator and Terminal Emulator II – cartridge based terminals support 110 and 300 baud, 7 bits even parity and has a proprietary terminal emulation mode allowing for graphics and sound, also only supports file transfers from TE compatible systems (TIBBS FOR INSTANCE)