User`s guide

Introduction 1-2
protects the transceiver should conformal coating or other forms of
environmental sealing be required on the printed circuit assembly.
The FTT-10A transceiver is compatible with Echelon's LPT-10 Link
Power Transceiver, and these transceivers can communicate with
each other on a single twisted pair cable. This capability provides an
inexpensive means of interfacing to nodes whose current or voltage
requirements would otherwise exceed the capacity of the link power
segment. When equipped with an FTT-10A transceiver, these nodes
can be operated from a local power supply without the need for
additional electrical isolation from the link power network.
The FTT-10A transceiver also provides electrical isolation for I/O
devices that are grounded, allowing such devices to be used on a link
power network segment. Each segment of a link power network
utilizes a non-isolated design with a single ground point at the LPI-10
Link Power Interface. Proper operation requires that the integrity of
a single point ground be maintained throughout the segment,
including I/O devices that are connected to a Neuron Chip. In many
applications, some I/O devices are grounded, either to meet functional
requirements or safety regulations. The transformer of the FTT-10A
transceiver electrically isolates the node from the segment, allowing
devices connected to the node to be grounded without impairing
communications.
A twisted pair channel may be comprised of multiple segments
separated by physical layer repeaters. A physical layer repeater
permits a twisted pair network to grow inexpensively to encompass
many more nodes or longer wire distances than would otherwise be
possible. The FTT-10A transceiver includes a physical layer repeater
feature that allows LonTalk
®
data to be exchanged between network
segments by interconnecting two or more FTT-10A or LPT-10
transceivers; FTT-10A-to-LPT-10 physical layer repeaters require the
addition of an external logic circuit. If the repeater includes an LPT-
10 transceiver then the internal power supply of the LPT-10
transceiver can power the FTT-10A transceiver. Alternately, the FTT-
10A transceiver can be powered by a local +5VDC power supply.
Using the FTT-10A transceiver can save literally thousands of hours
of development time compared with a custom-designed transceiver.
The transceiver is designed to comply with both FCC and EN55022
EMI requirements, minimizing time consuming and expensive
testing. As a UL Recognized component, the FTT-10A transceiver can
be integrated into a product without further safety testing. The
transceiver is small enough to fit into virtually any application, and is
economically priced for OEM applications of any volume.