Patent ID: 7426685

Claim:
A device for checking a transmission line carrying a plurality of digital and/or analogue channels comprising: a measurement block designed to evaluate performances, search for faults and determine the quality of the line and services transmitted through the transmission line; a switching module configured to selectively connect the measurement block only to the transmission channels to be checked and to keep other channels in the transmission line active; wherein the switching module comprises: a first low pass filter that maintains communication through at least one narrow band transmission channel between a public switch and a local loop; a first high pass filter that maintains communication through a broadband transmission channel; a second low pass filter connected to the measurement block; and a second high pass filter connected to the measurement block, wherein the first low pass filter and the second high pass filter are activated simultaneously in order to connect the measurement block only to the broadband transmission channel while maintaining a link through the narrowband transmission channel when the broadband transmission channel is to be checked, and wherein the first high pass filter and the second low pass filter are activated simultaneously in order to connect the measurement block only to the narrow band transmission channel while maintaining a link through the broadband transmission channel when the narrow band transmission channel is to be checked.