Chronological runs of printed cablegrams sent and received by the Department have been filed by post since January 1950. Until May 1974, cables were handled and filed in much the same way. Each message received a serial number inward, with an I prefix or outward with an O prefix. Numbers in both series started at 1 at the beginning of each year.

The introduction of full computerisation in 1974 led to the creation of new cable series with different numbering systems. All outward cable messages from Canberra received an O prefix and the identifying Canberra bigram CH (hard copy) or CE (electronic copy). In the new series, the cable numbers ran from 1 to 999999, then started again at 1. Post serial numbers (PSN) were still applied as a means of checking on whether all cables had been received, but cable serial numbers were normally used as the reference.

Printed copies continued to be filed in binders held alphabetically by post in two series - inward cables and outward cables. In order not to disrupt the system of chronological filing by year, cables from the old system covering January to May 1974 were filed in the 1974 binders with cables from the new system.

From July 1979, when the full database came into operation, cables were held on analog tapes and the printed chron runs came to an end. Registers of cable traffic were kept, but the loose leaf register sheets in use from 1961 to 1979 appear to have been destroyed.