The data type available for the TP1/Client interactive service is X_OCTET.

X_OCTET means a byte (character) array whose contents and operation are completely defined by the application. Therefore, the parameter that indicates the data length must be specified for X_OCTET to make it clear the length of the character array to be sent by communication management. The specified data length is provided as the len parameter for input of the interactive service, and is collected as the len parameter for output. The typed buffer specified here does not encode or decode data even when data is exchanged between machines of different models. X-OCTEX used for TP1/Client has no subtype.