Server User Manual
  Vlinx ESR90xW Hardware 
Documentation Number: ESR90xW-4905m  Chapter 2  11 
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 
Connectors 
Configuration Port Connector 
One standard RJ-45 receptacle that allows the serial server to be connected to 
personal computer for programming, troubleshooting and device 
configuration. A standard straight-through RJ-45 (male) Ethernet cable can 
be used for this purpose. (This port is not intended to connect directly to an 
Ethernet network.)
Antenna Connector 
The antenna connector is a reverse SMA connector. 
(An omni-directional antenna is supplied with ESR90xW wireless serial 
servers. All ESR90xW serial servers are FCC-certified when the supplied 
antenna is used.) 
Serial Port Connector(s) 
•  ESR901W232: One DB-9M connector 
•  ESR901W485: One five-terminal removable terminal block 
•  ESR902W: Two DB-9M connectors 
o  Port 1: RS-232 
o  Port 2: software selectable for RS-232, RS-422 or RS-485 
•  ESR904W: Four DB-9M connectors 
o  Ports 1 & 3: RS-232 
o  Ports 2 & 4: software selectable for RS-232, RS-422 or RS-
485 
Power Connector 
The power connector is a removable terminal block with four terminals. 
From top to bottom the terminals are: 
Terminal 
Number 
Terminal 
Name 
Connect to  Description 
1 
AC In 
One side of AC power supply (if AC 
power used) 
2 
AC In 
Other side of AC power supply (if 
AC power used) 
24 VAC 
1 
DC GND 
Negative side of DC power supply 
(if DC power used) 
Internally, the chassis ground of the 
Server is connected to this terminal. 
2 DC power 
supply 
Positive side of DC power supply (if 
DC power used) 
+12VDC to 30 VDC 
  Vlinx ESR90xW Hardware 
12   Chapter 2  Documentation Number: ESR90xW-4905m 
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 
RS-485 Receiver Biasing 
Vlinx ESR90xW wireless serial servers provide built-in receiver biasing on 
RS-485 ports (includes the 902W485 port, 902W Port 2 and 904W Ports 2 
and 4). The Data(+) line is pulled up to 3.3V supply using a 4.7 kΩ resistor 
and the Data(-) line is pulled down to ground, also using a 4.7 kΩ resistor. 
RS-422/485 Terminating 
If a terminating resistor is deemed necessary, for RS-422 operation typically 
a 120 Ω resistor would be connected across the Receive Data(+) and Receive 
Data(-) lines. For RS-485 operation the resistor would be connected across 
the Data(+) and Data(-) lines. 
For more information on Receiver Biasing and RS-422/485 Terminating access the 
B&B Electronics RS-422/485 Application Note available at www.bb-elec.com) 
Connections for Server Configuration 
Vlinx ESR90xW Wireless Serial Servers can be configured via: 
•  A wired connection to a RJ-45 Ethernet connector on the ESR90xW 
front panel. 
•  The wireless network 
The wired connection is recommended for configuration, especially when 
configuring wireless settings, to ensure communication is not lost while 
changing settings. 
Figure 6.  Wired Connection for Configuration 










