| 1 | UN/ECE level A | 
|  | As defined in the basic code table of ISO 646 with the exceptions of lower case letters, alternative graphic character allocations and national or application-oriented graphic character allocations. | 
| 2 | UN/ECE level B | 
|  | As defined in the basic code table of ISO 646 with the exceptions of alternative graphic character allocations and national or application-oriented graphic character allocations. | 
| 3 | UN/ECE level C | 
|  | As defined in ISO 8859-1 : Information processing - Part 1: Latin alphabet No. 1. | 
| 4 | UN/ECE level D | 
|  | As defined in ISO 8859-2 : Information processing - Part 2: Latin alphabet No. 2. | 
| 5 | UN/ECE level E | 
|  | As defined in ISO 8859-5 : Information processing - Part 5: Latin/Cyrillic alphabet. | 
| 6 | UN/ECE level F | 
|  | As defined in ISO 8859-7 : Information processing - Part 7: Latin/Greek alphabet. | 
| 7 | UN/ECE level G | 
|  | As defined in ISO 8859-3 : Information processing - Part 3: Latin alphabet. | 
| 8 | UN/ECE level H | 
|  | As defined in ISO 8859-4 : Information processing - Part 4: Latin alphabet. | 
| 9 | UN/ECE level I | 
|  | As defined in ISO 8859-6 : Information processing - Part 6: Latin/Arabic alphabet. | 
| 10 | UN/ECE level J | 
|  | As defined in ISO 8859-8 : Information processing - Part 8: Latin/Hebrew alphabet. | 
| 11 | UN/ECE level K | 
|  | As defined in ISO 8859-9 : Information processing - Part 9: Latin alphabet. | 
| 12 | UN/ECE level X | 
|  | Code extension technique as defined by ISO 2022 utilising the escape techniques in accordance with ISO 2375. | 
| 13 | UN/ECE level Y | 
|  | ISO 10646-1 octet without code extension technique. |