xtelld is daemon receiving messages from the xtell(1) client and displaying them to apropriate user.
Xtell daemon can run either from inetd(preferred) or from command line.
If you decide to start it from inetd, add this line to /etc/services :
xtell 4224/tcp # xtell server
and this line to /etc/inetd.conf :
xtell stream tcp nowait nobody.tty /usr/sbin/tcpd /usr/local/sbin/xtelld
Notice that the entries are separated by tabs, not spaces. Restart inetd with killall -HUP inetd
What to do if you are a normal user and want to run xtell daemon:
You can't run it from inetd, obviously. Just start ./xtelld to use xtell on default port (4224). In this case, xtell can write messages only to you. If there is another user on that system willing to get messages, either s/he starts xtelld on another port (e.g. ./xtelld -p4225), or makes his/her tty writable by you (e.g. chmod a+rw /dev/tty* /dev/pts/*)