APL TECHNICAL INFORMATION
Word in the process control industry is spreading about a new physical layer that supports
Ethernet communication and power transmission over a single twisted shielded pair cable. This
new physical layer is dubbed the Advanced Physical Layer, APL.
IEEE recently created a new Ethernet standard, IEEE 802.3cg, defining a new variant. The new variant is
sometimes referred to as Single Pair Ethernet, SPE. There are two sub-variants of this new Ethernet
10BASE-T1S This sub-variant was developed for use in automobiles or other short distance
applications to save on wiring costs. Other applications include building automation for such
things as elevators, HVAC, and lighting. It supports a multi-drop architecture (multiple devices
on a single cable).
10BASE-T1L (APL) This sub-variant was developed for longer distance communication
needs (up to 1 km) such as in continuous process control of refineries and chemical processing
plants. It supports a point-to-point architecture (each cable has only 2 devices). It is also
referred to as APL (Advanced Physical Layer).
See the following Application Notes for more detailed information (more to come!):