Parameter type: Keyword, optional

Purpose: Use the SUBCHARS parameter (supported by JES3 only) to specify a substitute (consisting of two characters) for the first two characters of /*EOF and /*DEL internal reader control statements. The substitute characters on the internal reader control statements must be in columns 1 and 2.

You can use the SUBCHARS parameter for any XMIT JCL job. However, SUBCHARS is required if you want to transmit internal reader control statements (/*EOF and /*DEL) and the job is processed by an internal reader on the sending system. Note that the system recognizes /*EOF and /*DEL as internal reader control statements and errors can occur on the sending system if /*EOF or /*DEL are included in the XMIT JCL stream.

To transmit internal reader control statements, replace /* on the /*EOF and /*DEL statements in the records to be transmitted with two substitute characters and identify the substitute characters on the SUBCHARS parameter. Prior to transmission, the system converts the substitute characters to /* and sends /*EOF and /*DEL to the receiving node for processing.

Reference: The internal reader is described in z/OS MVS Programming: Assembler Services Guide.