This article is from the Mac communications FAQ, by Bruce L Grubb BruceG6069@aol.com with numerous contributions by others.
Telnet is a high speed terminal connection protocol designed with TCP/IP
in mind. A Telnet program allows you to connect to computers that accept
Telnet sessions (such as UNIX boxes) with interactive full-screen
console input and output capabilities.
There are several Telnet programs for the Macintosh.
NCSA Telnet and succesors (BetterTelnet and MacTelnet)
The most widely known and used is the freeware NCSA Telnet
for which developement stopped January 1, 1996. The last
'offical' version was 2.6 though there is a 2.7b4 available.
There are serveral succesor programs which improve on the
NCSA Telnet code.
One such freeware successor is Sassy Software's BetterTelnet
(Version 2.0fc1) <http://www.cstone.net/~rbraun/mac/telnet/>
which uses the 2.7b5 code and provides many bug fixes, an
improved interface, and additional features. Both of these
programs support TEK 4105 graphics, provide both an FTP server
*and* client, and can do session logging. About the only drawback
is that these programs use Classic rather than Open Transport
MacTelnet <http://home.austin.rr.com/telnet/> is another such
program and is one of the few that states plans to be MacOS X
dataComet <http://www.databeast.com/> is both the oldest
(1986 as Cornell TN) and longest supported MacOS Telnet
application. This shareware application supports PC-ANSI,
VT220, & TN3270 terminal emulation, as well as serial
connections and communications protocols (including ZModem)
and suuports both 68K and PPC machines.
Nifty Telnet <http://andrew2.andrew.cmu.edu/dist/niftytelnet.html>
is a freeware Telnet program that supports Kerberous encrypting
(US version only), has a clean interface, and is Open Transport
$69.95 commercial program by InTrec Software
<http://www.intrec.com/proterm-mac/> with a 30 day free trial
that also supports a communiction connection (see 3.2)
If you need to telnet to an IBM mainframe this program at
version 2.5b5 this makes tn3270 more enjoyable.