Patent ID: 7009375

Claim:
A cable installation comprising: a backbone cable, a plurality of branch cables, splices coupling the branch cables to the backbone cable and tone conductors along the backbone and branch cables, the tone conductors being connected at the splices, and a cable locating system for locating the backbone cable and the branch cables, the system comprising: a tone source connected to the tone conductor of the backbone cable at an inner end of the backbone cable for transmitting a current signal on the tone conductors of the backbone cable and branch cables at a tone frequency; a plurality of terminations connected to the respective tone conductors at ends thereof remote from the tone source and the splices, each termination comprising: a load impedance connected between the respective tone conductor and a tone signal return path for discharge of current from the tone conductor; and an active component responsive to variations in a voltage in the load impedance to maintain a maximum amplitude of the current discharged at a substantially constant value.