An active terminating device (30) for an electrical 
transmission line with optional line-receiving and line-driving capabilities. The basic device is a two-
terminal unit, denoted as a 
Signal Canceling Unit (SCU), which sensesthe 
signal available at its terminals (34a, 34b), and applies 
negative feedback in order to cancel and absorb the 
signal. When applied to the end of a 
transmission line (15a, 15b) as part of 
wired communication network, the SCU functions as a terminator. When connected in the middle of such wired 
transmission line, the SCU splits the transmission line into two separate and isolated segments. In such a configuration, the SCU can be used to isolate a portion of a network from 
signal degradation due to 
noise or bridge-tap. Furthermore, the two isolated segments may each employ independent communications, such that no interference exists between the segments. In another embodiment, line 
receiver functionality is integrated into the SCU, designated as a 
Signal Canceling and Receiving Unit (SCRU) (90). The SCRU can perform all the SCU functions, and also serves as a line 
receiver in the communication network. In yet another embodiment, 
line driver functionality is integrated into the SCRU, designated as a 
Signal Canceling, Receiving and Transmitting Unit (SCRTU) (120). The SCRTU can perform all the SCRU functions, and also serves as a 
line driver in the communication network. Upon connecting multiple SCRTU's to a continuous transmission line, terminated 
independent point-to-point communication segments are formed.