Paired mode, Heart beat – B&B Electronics ESP904 - Manual User Manual
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Introduction
Manual Documentation Number: ESP904-4513m
Chapter 1
3
B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104 – www.bb-elec.com
B&B Electronics Ltd – Westlink Commercial Park – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445 – www.bb-europe.com
To use this mode, the ESP904 must be set to either TCP/server or 
UDP/server with a designated communication port number. The virtual COM 
driver is the TCP or UDP client. 
Paired Mode
Paired Mode
is also called serial tunneling. In this mode any two serial
devices that can communicate with a serial link will be able to communicate 
using two ESP904s and the LAN. 
Two ESP904s are connected to a network, one configured as a TCP or UDP 
client and the other as a TCP/UDP server. When setting up the server the 
remote IP address section must contain the address of the client. This will 
allow the client’s IP address to pass the IP address-filtering feature of the 
server. Conversely, the Remote IP address of the client must contain the 
server’s IP address. Both communication port numbers must be the same. 
Heart Beat
The
Heart Beat
protocol connection provides a reliable communications
connection in
Virtual COM Port Mode
or with
Paired Connection Mode
.
This feature restores the connection if communications are temporarily lost at 
either end due to loss of power or Ethernet connection. 
Without this feature a device that loses a connection and stops 
communicating would not be able to reconnect without human intervention. 
A TCP data connection can be lost when there is a power failure or 
temporary loss of an Ethernet connection on either the client or server. If a 
loss occurs the Heart Beat feature will try to reconnect the TCP data 
connection every five seconds until communications is established again. The 
Heart Beat feature is available for use in 
Virtual COM Port
Mode
and
Paired
Connection Mode
. This is not available when using a UDP application.
