Irssi is a command-line based IRC client available for Windows, OS X, Linux, as well as other very niche operating systems. It can be downloaded for free from the irssi website here.
After starting irssi, use the following command: "/network add -nick ADISC_USERNAME -user ANYTHING -realname ANYTHING NETWORKNAME" where ADISC_USERNAME is your ADISC username and where NETWORKNAME is the name you wish to give to the network you are configuring (the name is not important, so something like "ADISC" would work fine). The "ANYTHING" after -user and -realname can be replaced by, well, anything, keeping in mind what whatever you decide to put there will be visible by anyone that uses a /whois command on you.
You can now use the "/server add -auto -network NETWORKNAME adisc.org 6667 ADISC_PASSWORD" command if you wish to not use SSL encryption or the "/server add -auto -ssl -network NETWORKNAME adisc.org 7001 ADISC_PASSWORD" if you wish to use SSL encryption. NETWORKNAME is whatever you chose to name your network in the last step and ADISC_PASSWORD is your ADISC password.
You may now create a list of channels to connect to upon startup. The command is simply "/channel add -auto #chan_name NETWORKNAME" where #chan_name is, for example, #adisc.
You should now use the "/save" command to save all your configurations. When you restart irssi, you should see something like this: