TIdTCPClient = class(TIdTCPClientCustom);

TIdTCPClient is a TIdTCPClientCustom decendant that implements a TCP (Transmission Control Protocol) client. TIdTCPClient publishes properties and event handlers inherited from the TIdTCPClientCustom custom client. 

TIdTCPClient includes properties, methods, and events that provide the following capabilities for the client: 

• Get/Set Host and Port numbers for the connection.
• Get/Set Username and Password for the connection.
• Create or assign an IOHandler for the connection.
• An OnConnected event handler.
• Connect method to establish the connection to the peer.
• ConnectAndGetAll to connect, read available data, and disconnect.