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ProSoft Technology PLX31-EIP-SIE User Manual

Page 157

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PLX3x Series

ASCII Protocol

Ethernet and Serial Gateways

User Manual

ProSoft Technology, Inc.

Page 157 of 218

September 17, 2014

Transmit-Only Mode

A port on the gateway configured to function in transmit-only mode is set up to
only transmit data from the PLX3x gateway

’s internal database (received from an

external source) to an ASCII device. When the transmit driver (Tx Driver)
recognizes a new write block containing data (data placed in the gateway

’s

internal database), it transmits this data out to the port. The sequence number
used in the block will be different than that of the previous block, and therefore,
signals that the packet is fully assembled and ready to send. The following
illustration shows data flow for a transmit-only device.

Configuring a Port for Transmit-Only Mode
In order to set a port for Transmit-Only mode, ensure that the Tx DB Start
parameter in the configuration file contains the starting location of where the data
will be stored. The Rx DB Start parameter must contain a value of -1. This value
indicates that the port will not receive any data.