ReadTimeout is an Integer property that represents the number of milliseconds to wait for completion of a read request using the methods in the IOHandler. 

ReadTimeout is used in ReadFromSource to determine how the timeout argument passed to the method is interpreted. When the timeout argument passed to ReadFromSource contains the value IdTimeoutDefault, the value from ReadTimeout is used in the method. If the ReadTimeout property contains the value 0 (zero) or the symbolic constant IdTimeoutDefault, the value in IdTimeoutInfinite is used as the timeout interval. When ReadTimeout contains a positive non-zero value, the number of milliseconds is used as the timeout interval. 

IdTimeoutInfinite indicates that timeout values are ignored. 

The default value for ReadTimeOut is IdTimeoutDefault, as assigned during initialization of the component in the inherited constructor. 

Set the value in ReadTimeout to a larger value when using a client or a server on a low-bandwidth or congested network. 

Applications do not normally assign values directly to the ReadTimeout or ConnectTimeout properties in an IOHandler. Assign values to the corresponding properties in TIdTCPClient or a descendant class.

IdTimeoutDefault 

IdDefTimeout 

ReadFromSource 

TIdIOHandler 

TIdTCPClient