Rec. No.
Q.120 Definition and function of signals
Q.121 Signal code
Q.122 Signal sender
Q.123 Signal receiver
Q.124 Splitting arrangements
Q.125 Speed of switching in international exchanges
Q.126 Analysis and transfer of digital information
Q.127 Release of registers
Q.128 Switching to the speech position
Q.129 Maximum duration of a blocking signal
Q.130 Special arrangements in case of failures in the sequence of
signals
Q.131 Abnormal release conditions of the outgoing register causing
release of the international circuit
Q.133 Numbering for access to automatic measuring and testing
devices
Q.134 Routine testing of equipment (local maintenance)
Q.135 Principles of rapid transmission testing equipment
Q.136 Loop transmission measurements
Q.137 Automatic testing equipment
Q.138 Instruments for checking equipment and measuring signals
Q.139 Manual testing