| Nr | Cod National | Cod CAS | Prefix Romtelecom | Prefix RDS | Prescurtare | Denumire |
| 1 | 1 | 11 | 258 | 358 | AB | Alba |
| 2 | 2 | 21 | 257 | 357 | AR | Arad |
| 3 | 3 | 31 | 248 | 348 | AG | Argeș |
| 4 | 4 | 41 | 234 | 334 | BC | Bacău |
| 5 | 5 | 51 | 259 | 359 | BH | Bihor |
| 6 | 6 | 61 | 263 | 363 | BN | Bistrița-Năsăud |
| 7 | 7 | 71 | 231 | 331 | BT | Botoșani |
| 8 | 9 | 91 | 239 | 339 | BR | Brăila |
| 9 | 8 | 81 | 268 | 368 | BV | Brașov |
| 10 | 40 | 411 | 21 | 31 | B | București |
| 11 | 10 | 101 | 238 | 338 | BZ | Buzău |
| 12 | 51 | 401 | 242 | 342 | CL | Călărași |
| 13 | 11 | 111 | 255 | 355 | CS | Caraș-Severin |
| 14 | 12 | 121 | 264 | 364 | CJ | Cluj |
| 15 | 13 | 131 | 241 | 341 | CT | Constanța |
| 16 | 14 | 141 | 267 | 367 | CV | Covasna |
| 17 | 15 | 151 | 245 | 345 | DB | Dâmbovița |
| 18 | 16 | 161 | 251 | 351 | DJ | Dolj |
| 19 | 17 | 171 | 236 | 336 | GL | Galați |
| 20 | 52 | 231 | 246 | 346 | GR | Giurgiu |
| 21 | 18 | 181 | 253 | 353 | GJ | Gorj |
| 22 | 19 | 191 | 266 | 366 | HR | Harghita |
| 23 | 20 | 201 | 254 | 354 | HD | Hunedoara |
| 24 | 21 | 211 | 243 | 343 | IL | Ialomița |
| 25 | 22 | 221 | 232 | 332 | IS | Iași |
| 26 | 23 | 471 | 21 | 321 | IF | Ilfov |
| 27 | 24 | 241 | 262 | 362 | MM | Maramureș |
| 28 | 25 | 251 | 252 | 352 | MH | Mehedinți |
| 29 | 26 | 261 | 265 | 365 | MS | Mureș |
| 30 | 27 | 271 | 233 | 333 | NT | Neamț |
| 31 | 28 | 281 | 249 | 349 | OT | Olt |
| 32 | 29 | 291 | 244 | 344 | PH | Prahova |
| 33 | 31 | 311 | 260 | 360 | SJ | Sălaj |
| 34 | 30 | 301 | 261 | 361 | SM | Satu Mare |
| 35 | 32 | 321 | 269 | 369 | SB | Sibiu |
| 36 | 33 | 331 | 230 | 330 | SV | Suceava |
| 37 | 34 | 341 | 247 | 347 | TR | Teleorman |
| 38 | 35 | 351 | 256 | 356 | TM | Timiș |
| 39 | 36 | 361 | 240 | 340 | TL | Tulcea |
| 40 | 38 | 381 | 250 | 350 | VL | Vâlcea |
| 41 | 37 | 371 | 235 | 335 | VS | Vaslui |
| 42 | 39 | 391 | 237 | 337 | VN | Vrancea |
