Honeywell USI-0001

1.2 COMMONLY USED TERMS

The reader should be familiar with the following terms that are used

throughout this instruction manual:

MODBUS: Modbus is a digital data communication protocol which

provides a widely used set of standard commands by

which system data can be communicated to an external

device.

RS485: RS485 is an electrical standard that uses a twisted

pair cable carrying differential signals to transfer digital

data. RS485 permits up to 32 transceiver nodes to be

connected onto a single twisted pair highway for 'multidrop' bi-directional operation over distances up to 1.2km

(3900ft).

RS422: RS422 is an electrical standard that uses a twisted

pair cable carrying differential signals to transfer digital

data. RS422 permits a single driver and up to 10

receiver nodes to be connected onto the highway for

operation over distances up to 1.2km (3900ft).

RS232: RS232 is an electrical standard that uses multi-core

cable carrying signals to transfer digital data. RS232

permits interconnection of two communicating devices

for bi-directional operation over distances up to 15m

(49ft).

Baud Rate: Baud is a unit of signalling speed equal to the number

of discrete signal events per second. (Not necessarily

the same as bits per second).

Bit Rate: The speed at which bits are transmitted, usually

measured in bits per second (bits/s).

Parity: A technique used to detect single bit errors in a

transmitted data byte (character) in electronic code

transmission.

Stop Bit: A method to indicate the end of a

.