TAC is an open source

Open source

The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...

 instant messaging

Instant messaging

Instant Messaging is a form of real-time direct text-based chatting communication in push mode between two or more people using personal computers or other devices, along with shared clients. The user's text is conveyed over a network, such as the Internet...

 and chat client program written by AOL

AOL

AOL Inc. is an American global Internet services and media company. AOL is headquartered at 770 Broadway in New York. Founded in 1983 as Control Video Corporation, it has franchised its services to companies in several nations around the world or set up international versions of its services...

 which uses the TOC protocol

TOC protocol

The TOC protocol, or Talk to OSCAR protocol, was a protocol used by some third-party AOL Instant Messenger clients and several clients that AOL produced itself...

 used by the AOL Instant Messenger

AOL Instant Messenger

AOL Instant Messenger is an instant messaging and presence computer program which uses the proprietary OSCAR instant messaging protocol and the TOC protocol to allow registered users to communicate in real time. It was released by AOL in May 1997...

 system. It is written in Tcl, and is a command line client. It is a command line version of the GUI

Gui

Gui or guee is a generic term to refer to grilled dishes in Korean cuisine. These most commonly have meat or fish as their primary ingredient, but may in some cases also comprise grilled vegetables or other vegetarian ingredients. The term derives from the verb, "gupda" in Korean, which literally...

 TiK

TiK

TiK is an open source instant messaging client for the AOL Instant Messenger system, which uses AOL's TOC protocol. It is a GUI client which is written in the Tcl/Tk programming language...

 client which is written in Tcl

Tcl

Tcl is a scripting language created by John Ousterhout. Originally "born out of frustration", according to the author, with programmers devising their own languages intended to be embedded into applications, Tcl gained acceptance on its own...

/Tk. Developing of TAC and TiK

TiK

TiK is an open source instant messaging client for the AOL Instant Messenger system, which uses AOL's TOC protocol. It is a GUI client which is written in the Tcl/Tk programming language...

 began around 1998 or so. The software is no longer developed by AOL

AOL

AOL Inc. is an American global Internet services and media company. AOL is headquartered at 770 Broadway in New York. Founded in 1983 as Control Video Corporation, it has franchised its services to companies in several nations around the world or set up international versions of its services...

since 1999. Several independent developers have released some new versions of the software. However, at the time of this writing no new versions had been released for several years.