Omega Speaker Systems iLD Series manual Serial Communication Interfaces For Models with RS485 Port

2.4 Serial Communication Interfaces (For Models with RS485 Port)

The iLD Big Display controller/monitor with the Embedded Ethernet Server option board support only RS485/422 interfaces. These standards define the electrical characteristics of a communication network. The RS485 port of the Ethernet Server is fully compatible for use with RS422 instruments. The RS485 is an extended version of the RS422 communication standard which increases the allowable number of devices from 10 to 32 by improving the electrical characteristics.

•The RS485 standard (multi-point) allows one or more devices (multi-dropped) to be connected to the Ethernet Server using a two-wire connection (half-duplex) +Rx/+Tx and –Rx/-Tx. Use of RS485 communications allows up to 32 devices to connect to the Web Server with cable length up to 4000 feet long.

Although the RS485 is commonly referred to as a "two wire" connection, the Web Server also provides a ground/return shield connection to use as a common connection for EMI noise protection.

Table 2.2 shows some characteristics of the RS485 communication interface.

Table 2.2 Data Transmission Characteristics RS485

Data Transmission Characteristics	RS485
Transmission Mode	Differential
Electrical connections	2 wire
Drivers per line	32 drivers
Receivers per line	32 receiver
Maximum data rate	10M bits/s
Maximum cable length	4000 ft (1200 meters)

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