Method and device for estimating properties of a telecommunication transmission line

A device for estimating at least one transmission property of a telecommunication transmission line, the device comprising:

• means for sending at least one signal to the line;
• means for receiving a resulting signal from the line;
• and
• means for determining an estimate of the at least one transmission line property from the relationship between the at least one sent signal and the at least one resulting signal;
• wherein the at least one signal comprises at least two frequencies for which the absolute value of the line propagation constant times the line length is less than π.

A telecommunication exchange for estimating at least one transmission property of a telecommunication transmission line, the telecommunication exchange comprising:

• means for sending at least one signal to the line;
• means for receiving a resulting signal from the line;
• and
• means for determining an estimate of at least one transmission line property from the relationship between the at least one sent signal and the at least one resulting signal;
• wherein the at least one sent signal comprises at least two frequencies for which the absolute value of the line propagation constant times the line length is less than π.

A computer program loaded on an internal memory of an exchange in a communications system, comprising software code portions for performing the following steps when the computer program is run on a processor of the exchange:

• sending at least one signal to the line;
• receiving at least one resulting signal from the line;
• and
• determining an estimate of at least one transmission line property from the relationship between the at least one sent signal and the at least one resulting signal;
• wherein the at least one sent signal comprises at least two frequencies for which the absolute value of the line propagation constant times the line length is less than π.