What is expected with the CALL SYMPUT specifically? If you are looking to input data from an external file to combine with your other SAS dataset(s), the SAS conference paper (link below) demonstrates using the DATA step and the INPUT statement to build a SAS file from a sequential input.
Otherwise, if you have some specific INPUT and OUTPUT sample conditions to offer, beyond what can be accomplished with the processes explained in the referenced paper, please re-post with some explanation of the SAS macro variable purpose (where you mention CALL SYMPUT).
Scott Barry
SBBWorks, Inc.
Hands-On Introduction to SAS® DATA Step Programming
Debbie Buck, D. B. & P. Associates, Houston, TX
http://www2.sas.com/proceedings/sugi30/134-30.pdf