This Defence Standard (Def Stan) specifies telephone cables (internal) which are to be utilised in telephone, telegraph and allied systems for Ministry of Defence use.

Service requirements for telephone cables (external) are specified in Def Stan 61-12 Part 12 Section 1.

Table 1 to Table 4 list the standard range of cables from which selection shall be made for all new requirements for switchboard and distribution wiring.

Table 5 and Table 6 list the standard range of cables from which selection shall be made for all new requirements for jumper wiring.

The items listed in Table 1 to Table 6 shall also be used for the maintenance of existing systems. This standard does not therefore contain a Table listing "items permitted only for that purpose".

Table 8 lists items that are "no longer to be provisioned" and in each case shows the replacing item of Table 1.

The attention of users is drawn to the fact that as the temperature decreases PVC compounds becomes increasingly stiff and brittle, with the result that if the cable is bent too sharply or is struck at temperatures in the region of 0ºC or lower there is a risk of shattering the insulation. To avoid the risk of damage during handling it is necessary that these cables should be installed only when both the cable and the ambient temperature are above 0ºC, and have been so for the previous 24 hours, or when precautions have been taken to maintain the cable above this temperature.

This Standard is to be invoked in all tenders or contracts for the items in Table 1 to Table 6. Any items supplied must be wholly in conformity with its requirements. For codification purposes this Standard is to be listed among the reference data for the items in Table 1 to Table 6.