This Recommendation details the characteristics of an international leased circuit intended to form part of a private switched telephone network. The requirements of this Recommendation are intended to ensure the provision of a circuit suitable for telephony purposes. Such circuits may be used either singly, and thus provide for speech communication between two private telephone exchanges in different countries, or as part of a connection within a private switched telephone network covering two or more countries.

It should be noted that not all Administrations provide circuits of the type covered by this Recommendation.

Recommendation G.171 [1] contains the transmission planning considerations upon which the characteristics given in § 2 below are based, and specifies the maximum number of circuits in tandem which the transmission plan permits¹⁾.

¹⁾ Recommendation G.171, § 1 [1] states that for connection between private telephone networks and the public network, when permitted, "assurance cannot always be given that transmission performance to CCITT standards will be obtained." The same may be said for connections achieved by a user over which an Administration has no control, for example, between two or more private networks by virtue of user provided private automatic branch exchanges (PABXs).