The ICVTSD system initialization parameter specifies the terminal scan delay value.
ICVTSD={0|number} 
- The terminal scan delay facility was used in earlier
releases to limit how quickly CICS dealt with some types of terminal
output requests made by applications, in order to spread the overhead
for dealing with the requests. The range is 0 through 5000 milliseconds.
Specifying a nonzero value was sometimes appropriate where the CICS
system used non-SNA networks. However, with SNA and IPIC networks,
setting ICVTSD to 0 is appropriate to provide a better response time
and best virtual storage usage.
