In the period from circa 1977-1985, candidates who successfully passed an FCC amateur radio examination would be able to operate with their new (upgraded) privileges by appending "/" followed by the two-letter abbreviation of the  FCC Field Office or Resident Agent Office iin which they took the exam.  On phone, they would typically sign "W1XYZ temporary BS" or "WA3XYZ interim PA".  This was necessary until the printed licence was received in the mailed. The FCC offices and their codes are listed below. There may be some omissions from this list. Additional information please to Alan, 5B4AHJ, email address on QRZ.COM.

FCC Office Suffix Mapped by
Anchorage AK AR  Exception 
Atlanta GA AT


Baltimore MD BM Exception 
Boston MA BS


Buffalo NY

BF  No QSOs 
Chicago IL CG 


Columbia MD  WN


Dallas TX  DL  Exception 
Denver CO DV 


Detroit MI DT Exception
Honolulu HI  HL  Exception 
Houston TX HU Exception 
Kansas City MO KC  Prefix
Long Beach CA LB Exceptions 
Miami FL Info wanted   

Minneapolis–Saint Paul MN

PL  Exception 
New Orleans LA Info wanted   
New York NY NY  Prefix 
Norfolk VA  NF  Prefix 
Orlando FL OR  Exception 
Philadelphia PA PA 


Portland OR PO  Exception 
San Diego CA  SD Exception 
San Francisco CA  SF  Exception 
San Juan PR SJ  Exception 
Savannah GA SV  Exception 
Seattle WA ST Exception 
Tampa FL TP Exception 

More recently, those who have requested a licence modification (class upgrade) must add "/" followed by a two-letter sufex per the following table:

Licence class upgrade Suffix Mapped by
Novice to General KT Prefix
Novice or Technician to General AG Prefix

Novice, Technician, General or Advanced to Amateur Extra

AE Prefix


Jim Reisert, AD1C


May 1994 QST published by ARRL, pp 54-59 An Overview of Amateur Callsigns - Past and Present 

FCC EB - Regional & Field Offices

Wikipedia Amateur Radio Licensing in the United States