COMMUTER HAS TCASII TA; RA; RESPONDS WITH CLB.

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AT 5000 FT ON A 360 DEG HDG; WE RECEIVED AN ATC TA FOR ACFT B WHICH WE DID NOT HAVE INITIALLY; BUT DID GET SHORTLY AFTER (ABOUT 5 SECONDS). OVER THE NEXT 30 SECONDS OR SO THE FREQ WAS CONGESTED SO WE COULD NOT LET ATC KNOW WE HAD ACFT B VISUALLY; OR QUERY THEM ABOUT THE OTHER TFC ON TCASII (ACFT A) IN ORDER THAT WE MIGHT RECEIVE A HDG CHANGE OR OTHER CLRNC. ATC NEVER ISSUED THE VFR TFC (ACFT A) SO WE DIDN'T KNOW IF ACFT A WAS IN RADIO OR RADAR CONTACT WITH TOLEDO DEP OR JUST FLYING AROUND (UNMONITORED). THE TCASII ISSUED A TA FOR ACFT A THEN AN RA 'MONITOR VERT SPD' I.E.; DO NOT DSND THEN 'CLB; CLB' WE CLBED AS INSTRUCTED; WHILE MAINTAINING VISUAL WITH ACFT B ONCE WE GOT ACFT A IN SIGHT. WE INITIATED A RETURN TO 5000 FT; AT WHICH TIME WE WERE ISSUED ANOTHER TA AND RA 'DSND; DSND' FOR ACFT B WHICH WE STILL HAD IN SIGHT (AND COMPLIED WITH RA). THE TCASII EVENT HAPPENED OVER A 30-45 SECOND TIME FRAME. ATC TOLD US 'MAINTAIN 5000 FT' AFTER WHICH TIME; WHEN FREQ CONGESTION ALLOWED; WE TOLD ATC WHAT HAPPENED. ATC RESPONDED 'OK; YOU SCARED ME...SORRY MA'M WE HAD A TCASII RA; WE HAVE THE 6000 FT TFC IN SIGHT.' THE FLT PROGRESSED NORMALLY FROM THERE.