
A-2
Appendix A – Physical Layer Repeaters
Physical Layer Repeaters
Each link power transceiver incorporates a physical layer repeater function. If a link
power system grows beyond the maximum number of transceivers or total wire
length, then additional link power systems can be added by interconnecting
transceivers using the physical layer repeater function (figure A.1). The physical
layer repeater will transfer all LonTalk packets between the two segments,
potentially doubling the number of transceivers as well as the total length of wire
over which they communicate. The physical layer repeater function permits a link
power system to grow as system needs expand, without retrofitting existing
controllers or requiring the use of specialized bridges. Note that systems requiring
high levels of network traffic may benefit from the use of L
ON
W
ORKS
routers, which
forward packets only when necessary. L
ON
M
ARK
Interoperability requires that there
be a maximum of one repeater between any two LPT-11 or FTT-10A devices.
Original System
Expansion
48VDC
Power
Supply
LPI-10
Interface
LPT-11
Transceiver
FTT-10A
Transceiver
48VDC
Power
Supply
LPI-10
Interface
LPT-11
Device
LPT-11
Device
LPT-11
Device
LPT-11
Device
LPT-11
Device
LPT-11
Device
Link
Power
Repeater
LONWORKS
Router
L
ON
W
ORKS
Router
or
Figure A.1
Link Power Repeater and Router Options for System Expansion