Narrative:

Departed 19L at iad. Tower told us to turn right to 230 degrees and contact departure control. First officer flying. Captain attempted to contact departure on 126.65. First 2 calls were not answered. Third call got the reply 'this is washington departure, go back to your last frequency.' my reply was that we were supposed to contact washington departure. Departure control then told us we were on 126.55. We were now level 4000 ft on a 230 degree heading. I immediately channeled to 126.65. Washington departure called us, told us to turn right to 290 degrees, climb immediately to 10000 ft. Traffic 11 O'clock 3 mi at 3700 ft. We executed a 40-60 degree bank turn to 290 degrees, rate of climb went to 5000 FPM. TCASII sounded a TA with yellow symbol showing 600 ft. This advisory lasted 2 verbal calls, then stopped. We were on 126.55 for less than 30 seconds. We had WX radar on and TCASII in automatic mode so we could not get a range or bearing on the target. I think departure controls in general should identify themselves as to the airport they are serving, rather than the general locale.

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Original NASA ASRS Text

Title: AN MLG ACR WENT TO THE WRONG DEP CTL FREQ, THEN HAD A TCASII COMMAND IN IMC.

Narrative: DEPARTED 19L AT IAD. TWR TOLD US TO TURN R TO 230 DEGS AND CONTACT DEP CTL. FO FLYING. CAPT ATTEMPTED TO CONTACT DEP ON 126.65. FIRST 2 CALLS WERE NOT ANSWERED. THIRD CALL GOT THE REPLY 'THIS IS WASHINGTON DEP, GO BACK TO YOUR LAST FREQ.' MY REPLY WAS THAT WE WERE SUPPOSED TO CONTACT WASHINGTON DEP. DEP CTL THEN TOLD US WE WERE ON 126.55. WE WERE NOW LEVEL 4000 FT ON A 230 DEG HDG. I IMMEDIATELY CHANNELED TO 126.65. WASHINGTON DEP CALLED US, TOLD US TO TURN R TO 290 DEGS, CLB IMMEDIATELY TO 10000 FT. TFC 11 O'CLOCK 3 MI AT 3700 FT. WE EXECUTED A 40-60 DEG BANK TURN TO 290 DEGS, RATE OF CLB WENT TO 5000 FPM. TCASII SOUNDED A TA WITH YELLOW SYMBOL SHOWING 600 FT. THIS ADVISORY LASTED 2 VERBAL CALLS, THEN STOPPED. WE WERE ON 126.55 FOR LESS THAN 30 SECONDS. WE HAD WX RADAR ON AND TCASII IN AUTO MODE SO WE COULD NOT GET A RANGE OR BEARING ON THE TARGET. I THINK DEP CTLS IN GENERAL SHOULD IDENT THEMSELVES AS TO THE ARPT THEY ARE SERVING, RATHER THAN THE GENERAL LOCALE.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.