Open Unit Numbers
CODE RADIO SERVICE 
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 AA AVIATION AUXILIARY GROUP 
 AC CIVIL AIR PATROL 
 AD AVIATION DEVELOPMENTAL 
 AF AERONAUTICAL AND FIXED GROUP 
 AG AIRCRAFT GROUP 
 AR AVIATION RADIONAVIGATION LAND 
 AX AERONAUTICAL MOBILE SATELLITE 
 BA AUXILIARY BROADCAST 
 BF FM BROADCAST 
 BI INTERNATIONAL BROADCAST 
 BS STANDARD BROADCAST 
 BT TV BROADCAST 
 CA INDIVIDUAL MOBILE RADIO 
 CC INTERNATIONAL FIXED PUBLIC CONTROL 
 CD DOMESTIC PUBLIC LAND MOBILE 
 CE DIGITAL ELECTRONIC MESSAGE SERVICE 
 CF POINT TO POINT MICROWAVE 
 CG DOMESTIC PUBLIC AIR-GROUND 
 CI INTERNATIONAL FIXED PUBLIC 
 CL CELLULAR TELECOMMUNICATIONS 
 CM MULTI POINT DISTRIBUTION 
 CO OFFSHORE RADIOTELEPHONE (ORTS) 
 CP INTERNATIONAL FIXED PUBLIC PRESS 
 CR RURAL RADIO 
 CS INTERNATIONAL FIXED SATELLITE 
 CT LOCAL TELEVISION TRANSMISSION 
 CX DOMESTIC FIXED SATELLITE 
 EX EXPERIMENTAL EXPORT 
 GA CONVENTIONAL PUB SAF & SPEC EMERGENCY 
 GB CONVENTIONAL BUSINESS GROUP 
 GC MOTOR CARRIER GROUP 
 GF CONV PUB SAF & SPEC EMER - NATIONAL PLAN
 GI CONVENTIONAL OTHER INDUST & LAND TRAN 
 GO OTHER SERVICES GROUP 
 GP CONVENTIONAL PUB SAFETY & SPEC EMERGENCY 
 GR CONVENTIONAL SMR 
 GS 900 MEGAHERTZ PAGING 
 GU CONVENTIONAL BUSINESS 
 GX MIXED SERVICES GROUP 
 HA AMATEUR 
 HR RACES 
 HS AMATEUR SATELLITE 
 IB BUSINESS 
 IF FOREST PRODUCTS 
 IG BUSINESS INDUSTRIAL / POOL 
 IM MOTION PICTURE 
 IP PETROLEUM 
 IS SPECIAL INDUSTRIAL 
 IT TELEPHONE MAINTENANCE 
 IV FILM AND VIDEO PRODUCTION 
 IW POWER 
 IX MANUFACTURES 
 IY RELAY PRESS 
 LA AUTOMOBILE EMERGENCY 
 LI INTERURBAN PASSENGER 
 LJ INTERURBAN PROPERTY 
 LP LOW POWER 
 LR RAILROAD 
 LU URBAN PASSENGER 
 LV URBAN PROPERTY 
 LX TAXICAB 
 MA MARINE AUXILIARY GROUP 
 MC COASTAL GROUP 
 MK ALASKA GROUP 
 MR MARINE 
 MS SHIP GROUP 
 MX MARITIME MOBILE SATELLITE 
 NC NATIONWIDE COMMERCIAL 5 CHANNEL 
 NL NATIONWIDE NON-COMMERCIAL 10 CHANNEL 
 NS NATIONWIDE NON-COMMERCIAL 5 CHANNEL 
 PF FIRE 
 PH HIGHWAY MAINTENANCE 
 PL LOCAL GOVERNMENT 
 PM EMERGENCY MEDICAL 
 PO FORESTRY CONSERVATION 
 PP POLICE 
 PS SPECIAL EMERGENCY 
 PW PUBLIC SAFEY POOL 
 QD NON NATIONWIDE DATA 
 QM NON NATIONWIDE PUBLIC SAFETY / MUTUAL AID
 QO NON NATIONWIDE OTHER 
 QT NON NATIONWIDE 5 CHANNEL TRUNKED 
 RA RADIO ASTRONOMY 
 RP REMOTE PICKUP 
 RS RADIOLOCATION 
 SF STANDARD FREQUENCY 
 SM INDUSTRIAL SCIENTIFIC AND MEDICAL 
 TR CABLE TELEVISION RELAY 
 XC EXPERIMENTAL CONTRACT (DEV) 
 XD EXPERIMENTAL DEVELOPMENTAL 
 XR EXPERIMENTAL RESEARCH 
 YA TRUNKED PUB SAF & SPEC EMERGENCY 
 YB BUSINESS GROUP 
 YF TRNK PUB SAF & SPEC EMER - NATIONAL PLAN
 YG TRUNKED INDUSTRIAL / BUSINESS POOL 
 YI TRUNKED OTHER INDUSTRIAL & LAND TRANSPORATION
 YO OTHER SERVICES GROUP 
 YP TRUNKED PUB SAFETY & SPEC EMERGENCY 
 YS TRUNKED SMR 
 YU TRUNKED BUSINESS 
 YW TRUNKED PUBLIC SAFETY POOL 
 YX TRUNKED SMR 
 ZA GENERAL MOBILE 
 ZA GENERAL MODILE RADIO 
 ZC RADIO CONTROL 
 ZD CITIZENS BAND 
 ZV INTERACTIVE VIDEO & DATA