User`s guide

LONWORKS FTT-10A Transceiver User’s Guide 1-1

Introduction

The FTT-10A Free Topology Twisted Pair Transceiver provides a

simple, cost-effective method of adding a L

ONWORKS transceiver to

any Neuron

Chip-based control system. A replacement for the

popular FTT-10 transceiver, the FTT-10A transceiver supports

polarity insensitive, free topology wiring, freeing the system installer

from the need to wire using a bus topology (differences between the

FTT-10A and FTT-10 transceivers are described in Appendix A). Star,

bus, and loop wiring are all supported by this architecture. Free

topology wiring reduces the time and expense of system installation by

allowing the wiring to be installed in the most expeditious manner. It

also simplifies network expansion by eliminating restrictions on wire

routing, splicing, and node placement.

The FTT-10A transceiver consists of an isolation transformer that is

integrated with a 78kbps differential Manchester coded

communication transceiver. Pins are provided for connections to the

Neuron Chip Communications Port (CP) and clock lines, +5V power,

and the twisted pair network. The FTT-10A transceiver provides

automatic detection of the input clock frequency at 5, 10, and 20MHz.

The pins are keyed to prevent accidental reversal during mounting.

The FTT-10A transceiver appears as a high impedance to the network

when unpowered, and does not interfere with network

communications when powered down.

The transceiver is housed in an encapsulated plastic shell which

contains the transformer and signal processing electronics. The

compact package is only 7.2mm (0.28 inches) high and is ideal for use

in low profile applications such as DIN packs. The sealed housing