rdisp/delayed_call_interval is a SAP Parameter attribute which is used to control Time cycle for invoke of delayed functions information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
rdisp/delayed_call_interval defines the time internal in which it is
checked if scheduled internal functions are supposed to expire.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.