As automobile functions continue to become more advanced, automotive Ethernet standards such as 100BASE-T1 and 1000BASE-T1 are becoming widespread for in-vehicle communication. Furthermore, Multi-Gig Ethernet standards such as 2.5GBASE-T1, 5GBASE-T1, and 10GBASE-T1 have emerged to address the demand for high-speed communications. In automotive Ethernet standards such as 100BASE-T1 (IEEE 802.3bw standard) and 1000BASE-T1 (IEEE 802.3bp standard), the use of cost-effective UTP (Unshielded Twisted Pair) cables is allowed, and it is common to use them in combination with common mode chokes (CMC) for noise suppression to satisfy the performance specified by UTP cables and the OPEN Alliance.
On the other hand, configurations using STP (Shielded Twisted Pair) cables have been adopted in 2.5G/5G/10GBASE-T1 Multi-Gig Ethernet (IEEE 802.3ch standard). Because STP cables are considered to have high noise resistance, IEEE 802.3ch standard does not specify the installation of CMCs as a mandatory requirement. Since it is true that STP cables are UTP cables with an added conductor shield, they are effective in reducing noise emissions from twisted pairs and the impact of exogenous noise, which are among the weaknesses of UTP cables. However, simply switching a communication cable to an STP cable does not solve the problems of emission noise, common mode noise, ESD, etc.