Format of telephone/fax numbers

Many CIF data items take as value a telephone or fax number (e.g. _publ_contact_author_phone). The convention for expressing a telephone or fax number is as follows. A complete telephone or fax number may be defined by concatenating

• the international dialling prefix
• the area code in parentheses (without the area code initial digit as used for internal communications - see the first example below)
• the local number

and optionally

• the character "x" followed by an extension number

The convention in the Core dictionary version 1.0, where the international dialing prefix was given in parentheses and an extension was indicated by the string "ext" (e.g. '(44) 1244 342878 ext 212'), is no longer recommended for writing CIFs, but CIF readers should accept it.

Examples

44(1244)342878x212

The telephone extension of the COMCIFS Coordinating Secretary at Chester (area code 01244), UK (international code 44)

44(1244)314888

The fax number of the IUCr office in Chester, UK

33()556846152

A telephone number in France, where area codes are not supported