User manual

ZyWAN User Manual Configuring the ZyWAN

Field/Option Explanation

Full Duplex: This mode is designed for unsolicited data from

serial devices, full bi-directional communication, or any serial

protocol which may send large or multiple responses to a

request. In this mode, the Terminal Server constantly receives

data on both the serial and network ports, as long as a client is

connected to the IP Port.

Modbus Mode

Select the mode of operation, if Modbus protocol translation is

required. Options available are:

None: This is the normal option for most applications.

Open Modbus to ASCII: Converts Open Modbus/IP protocol

requests to serial Modbus ASCII protocol, and converts the

ASCII response to an Open Modbus/IP response.

Open Modbus to RTU: Converts Open Modbus/IP protocol

requests to serial Modbus RTU (Binary) protocol, and converts

the RTU response to an Open Modbus/IP response.

Serial Driver

Select whether to use the Native Linux (ttyS) serial driver, or the

Eurotech Ltd driver which allows for half-duplex RS-485

communication. Presently the Eurotech Ltd driver is not

available.

Broadcast Only

Select Yes to only send to the serial port. This option allows the

network computer to send data to the serial port without waiting

for a response. The Response Timeout and Duplex mode are

ignored.

Demark IP Packets

If a large network packet is sent to the ZyWAN and gets broken

up over the network, the fragments can sometimes arrive at

slightly different times. Each packet is sent to the serial port, but

if the time difference is too great, the serial device may not react

properly. Set this value to Yes to allow delayed IP packets to be

put together before sending to the serial port. The value for

Demark Timer is used to specify the time to wait for additional IP

data. Set this value to No if this feature is not needed.

Echo Cancel RS-

485

This option is used when the internal (COM3) or an external RS-

485 converter is used in half-duplex mode. Set this option to Yes

to block the reception of echo bytes on the serial port which get

echoed back from the RS-485 device.