IEEE 802.3 100Base-T1
100Base-T1 is an Ethernet interface for 100 Mbit/s, using single-pair UTP cable or STP cable: Single-Pair Ethernet( SPE). The interface is based on BroadR-Reach and was standardized by the IEEE working group802.3bw. Like the Gigabit interface1000Base-T1, it is used in automotive Ethernet.
Since weight saving is of enormous importance in automotive technology, the simple, unshielded wire pair of 100Base-T1 contributes to weight saving. As for the other Ethernet characteristics, the Ethernet frame format is maintained at the MAC level, as are the frame length limits of 802.3. 100Base-T1 uses multivalued pulse amplitude modulation( PAM-3), it transmits differential signals in full duplex, supports a data rate of 100 Mbps, and has an error rate of less than `10^-10`. In addition, the standard does not exclude autonegotiation. The cable length can be up to 40 m.
The IEEE working group 802.3bu has standardized a method for the transmission of supply voltages via the UTP cable for 100Base-T1 under the name Power over Data Lines( PoDL).