The Convention is complemented by three sets of detailed administrative rules (as indicated in Article 83): the Radio Regulations, the Telegraph Regulations and the Telephone Regulations.

But only in transmission over the telegraph lines and subject to the application of the International Telegraph Regulations.

The code employed for telegraphy must be the Morse code specified in the Telegraph Regulations annexed to the International Telecommunication Convention.

A succession of conferences followed, revising and redrafting the Telegraph Regulations to keep up with technical and administrative progress.

Following the patenting of the telephone in 1876 and the subsequent expansion of telephony, ITU decided in 1885 to add regulations for "the international telephone service" to the Telegraph Regulations.