10 base-T transmission over existing telephone wire within homes

Existing in-home telephone wire can be used to create a 10Base-T (10 Mbps Ethernet) customer premises network (CPN) that may be used to connect consumer electronic devices to a hub or to a residential gateway (RG). This paper presents measurements of attenuation and crosstalk performance at 10Base-T frequencies made on four different types of in-home telephone cables, including quad and twisted-pair. Computer simulations use the measured response of the cables to determine the performance of 10Base-T transmitted over them. Simulations are verified by experimental transmission tests using a LAN analyzer. It is found that some of the in-home telephone cables have good performance, which actually exceeds that of the Category 3 wiring specified for 10Base-T use. Some of the cables are not so good and do not even come close to meeting Category 3 specifications. Even so, 10Base-T was able to transmit error-free over 100 meters (328 ft) of the worst cable tested here with no bridged taps. Tree-and-branch wiring has unterminated branches connected to the cable between the transmitter and receiver. These branches are called bridged taps. It was found that 10 Base-T can function with bridged taps shorter than about 8 ft, but bridged taps longer than about 12 ft generally cause 10 Base-T to fail.