It depends a lot on whether or not your program is going to wait around for
the input, or if it needs to do something else while waiting. Or whether or not your input will come from a keyboard (time between characters) or all at once.

One way would be to -


Code:
 
LookForStart:
 
 
FoundStart = 0  
 
 
HSERIN 1000,NoData,[WAIT ("start")] : FoundStart=1
 
 
Return
 
 
 
 
 
NoData:
 
 
Return
FoundStart will = 1 if the "start" was received after waiting for 1 second.