The present invention provides a method of optionally changing damping characteristics of a twin-tube shock absorber. In response to identifying the operation mode of the communication device in which the communication device is to comply with the interference requirement, reducing noise generated by the communication device by selectively increasing a root mean square value of a time-varying current generated by a power source of the communication device. The method further includes the steps of marking each end of the cable such that the determined compensation length is visibly shown, forcing the cable into the pipe at an ambient installation temperature such that a cable pattern is formed therein, and maintaining the cable in the pipe to prevent the cable from being pushed out of the pipe.