Signalling Procedures - at an Incoming R2 Register Situated in a Transit Exchange - Specifications of Signalling Systems R1 and R2 (Study Group XI) 2 PP
When the outgoing link connects to a further international transit exchange signal A-11 must be used to request a country code indicator. On recognition of signal A-11 the outgoing international R2 register must send a country code indicator (signal 1-12