Text-based communications over a data network

A system for the use in a packet-based network, comprising:

• a user interface including at least one selector to start a text-based communications session and a portion to receive user-input text;
• and
• a controller adapted to create one or more Session Initiation Protocol messages to carry the user-input text, the user-input text embedded in the one or more Session Initiation Protocol messages.

A data signal embodied in a carrier wave containing a data structure accessible by elements coupled to a packet-based network, the data structure comprising:

• a header portion defined according to a protocol providing for audio based call sessions;
• a body portion containing a text-based chat string, wherein the data structure is defined according to a Session Initiation Protocol message, wherein the text-based chat string is embedded in the Session Initiation Protocol message.

A method of text-based messaging over a packet-based network, comprising:

• receiving messages defined according to a Session Initiation Protocol providing for audio-based communications, the messages including text exchanged in a text-based communications session and embedded in the Session Initiation Protocol messages;
• and
• determining if the received messages are to be blocked or permitted to be transferred between a first network and a second network.

A system, comprising:

• interfaces to a first network and a second network;
• and
• a firewall module to control access between the first and second networks, the firewall module allowing messages according to a Session Initiation Protocol defining audio-based call sessions to be passed between the first and second networks, wherein a text-based chat message is embedded in each of the Session Initiation Protocol messages.