Lantronix Device Server MSS 485 User manual

MSS485 Installation Guide
For the Lantronix MSS485 Micro Serial Server

i
Contents
1 Introduction
1.1 RS-485 Networking Overview.................................1-2
1.1.1 RS-485 Protocols....................................1-2
1.1.2 Two-wire Mode.....................................1-2
1.1.3 Four-wire Mode....................................1-3
1.2 Terms...........................................................................1-4
1.3 Protocols......................................................................1-5
1.4 Software ......................................................................1-6
1.5 Configuration.............................................................1-6
2 Installation
2.1 MSS485 Components.................................................2-1
2.2 Installation ..................................................................2-3
2.2.1 Power-up Diagnostics..........................2-6
2.3 Is It Working?.............................................................2-7

ii
3 Getting Started
3.1 IP Address Configuration.........................................3-2
3.1.1 Using a BOOTP or RARP Reply.........3-2
3.1.2 Using an ARP Entry and the Ping Command3-
2
3.1.3 Using the Serial Console......................3-3
3.2 Incoming Logins ........................................................3-4
3.2.1 Controlling Incoming Logins..............3-4
3.2.2 EZWebCon Login and Configuration3-4
3.2.3 Other Incoming TCP/IP Logins.........3-4
3.2.4 Incoming LAT Logins ..........................3-5
3.3 Serial Port Logins.......................................................3-5
3.4 Remote Console Logins ............................................3-5
3.5 Starting Outbound Connections..............................3-6
3.5.1 Telnet......................................................3-6
3.5.2 SPX..........................................................3-7
3.5.3 LAT .........................................................3-7
3.6 Logout..........................................................................3-7
4 Configuration
4.1 Command Set.............................................................4-1
4.2 System Passwords .....................................................4-1
4.2.1 Privileged Password.............................4-1
4.2.2 Login Password.....................................4-2
4.3 Protocol Configuration .............................................4-2
4.3.1 TCP/IP Parameters ..............................4-2
4.3.2 IPX/SPX Parameters ............................4-3
4.3.3 LAT Parameters ....................................4-4
4.4 Serial Port Configuration.........................................4-4

iii
5 Using the MSS
5.1 Host-Initiated Connections ......................................5-2
5.1.1 Socket Connections...............................5-2
5.1.2 LAT Connections..................................5-3
5.1.3 Host Applications.................................5-4
5.1.4 Code Examples......................................5-4
5.2 Interactive Connections ............................................5-5
5.2.1 Session Control......................................5-5
5.2.2 Outgoing Connections.........................5-7
5.2.3 Status Displays......................................5-9
5.3 Emulating a Direct Serial Connection.....................5-11
5.4 Multihost Mode..........................................................5-13
A Technical Support
B Troubleshooting
C Pinouts
D Specifications
Warranty Statement
Declaration of Conformity
Index

Introduction
1 - 1
1 - Introduction
The MSS485 is a multiprotocol serial server that provides Ethernet
connections for devices connected to an RS-485 network.
This manual explains how to install the MSS.
• The remainder of this chapter outlines MSS functionality.
• Chapter 2, Installation , explains how to install the MSS hardware
and boot the server.
• Chapter 3, Getting Started , details different ways to log into the MSS
and prepare the server for configuration.
• Chapter 4, Configuration , covers basic configuration.
• Chapter 5, Using the MSS , provides an overview of how to use the
MSS interactively and with host applications.
• Appendices provide information on Technical Support,
Troubleshooting, Pinouts, and Specifications.
• The hypertext version of this manual, located on CD-ROM,
includes more specific information about configuring and using the
MSS and reloading MSS software.
Be sure to read the section of the configuration chapter that applies to the
protocol you are using (TCP/IP, IPX/SPX, or LAT).
For more detailed information on the MSS, including a complete
command reference, see the
MSS Reference Manual located on the CD in
HTML, PDF, and PostScript formats.
To access the HTMLversion of the Reference Manual on the CD, use your
web browser’s Open or Open File command (usually in the File menu)
to open the file index.htm in the root directory of the CD. Then click on the
link to the MSS Reference Manual .
The PostScript and PDF versions of the MSS485 manuals are located in
the manuals directory of the CD. Use the Adobe Acrobat Reader (widely
available on the Internet at no charge) to read and print all or parts of the
manual from the file mssref.pdf .

RS-485 Networking Overview Introduction
1 - 2
1.1 RS-485 Networking Overview
The RS-485 standard allows a transmission line to be shared like a “party
line.” As many as 32 devices can share the multidrop network. Typically,
one device is the master and the other devices are slaves. There are a few
important things to note about RS-485 networking with the MSS.
• The MSS can be used in either two-wire or four-wire mode. Refer
to the following sections to determine which mode to use.
• The maximum RS-485 network cabling length (without repeaters)
is 4,000 feet. Lantronix recommends the use of shielded twisted-
pair cabling.
1.1.1 RS-485 Protocols
A large number and variety of protocols run over RS-485. However, the
MSS does not convert or interpret serial data. It only moves data between
serial and Ethernet. Any RS-485 protocol will have to be implemented by
host software.
1.1.2 Two-wire Mode
In two-wire mode, the MSS operates in half duplex: one pair of wires
shares transmit and receive signals, and an optional third wire can be
used for shield/ground. The main advantage of using two-wire mode is
reduced cabling costs.
Figure 1-1: Example Two-wire Mode Network
•
•
•
•
TXA
TXB
TX
RX
Shield
A
A
B
B
A
B
B
A
RX
TX
Shield
Shield
Shield •
•
•
A
B
A
B
TX
RX Sh
Sh •
•••
•
•
A
B
A
B
TX
RX Sh
Sh •
•••
•
•
A
B
A
B
TX
RX Sh
Sh •
•••
•
Shield
Slave Slave Slave
Slave
MSS
(Master)

Introduction RS-485NetworkingOverview
1 - 3
On a two-wire RS-485 network, the MSS must turn its transmitter on
when it is ready to send data and then off a certain period of time after
the data has been sent so that the line is available to receive again. At
most baud rate settings, the timing delay is typically one character length
with a maximum of 1.5 character lengths.
NOTE: For 600 baud and 4800 baud operation, the timing delay is
doubled.
1.1.3 Four-wire Mode
In four-wire mode, the MSS operates in full duplex: one pair of wires
functions as the transmit pair, another pair of wires functions as the
receive pair, and there is a shield/ground wire for each pair. In a four-
wire RS-485 network, one device, such as the MSS, acts as master while
the other devices are slaves.
Figure 1-2: Example Four-wire Mode Network
It is important to connect the transmitter of the master device to the wire
that is connected to the receive terminals on the slave devices, and
connect the receiver of the master device to the wire that is connected to
the transmit terminals on the slave devices. In essence, the master device
will be connected to the slave devices with a
swapped cable.
The MSS transmitter is always driving and the receiver is always enabled,
so the MSS is able to send and receive data simultaneously. The
advantages of four-wire mode are double the throughput of two-wire
mode and a guaranteed open path to each slave device’s receiver.
TX
RX
RX
TX
TXA
TXB
RXB
RXA
Shield
Shield
TXA
TXB
RXB
RXA
Shield
Shield
ShA
A
B
B
TX
RX Sh
•
•
•
•
•
•
ShA
A
B
B
TX
RX Sh
•
•
•
•
•
•
ShA
A
B
B
TX
RX Sh
•
•
•
•
•
•
MSS
Slave Slave Slave
Slave
(Master)

Terms Introduction
1 - 4
1.2 Terms
In this manual, the following terms are used to describe parts of a network.
Host A computer attached to the network. The term
host is generally used to denote interactive
computers, or computers that people can log into.
Node Any intelligent device directly connected to the
Ethernet network such as a host, a printer, or a
terminal server.All nodes have their own Ethernet
addresses. The MSS is a node. Devices connected
to the MSS are not nodes.
Master The device that controlls all other devices on an
RS-485 network. An RS-485 network typically has
one master device.
Slave Any device on the RS-485 network that is not the
master.An RS-485 network can have up to 31 slave
devices.
Session A logical connection to a service. A typical session
is a terminal connected to a host through the
server.
Local mode The MSS user interface. It is used to issue
configuration and session management
commands and to establish connections. When in
Local mode, users will see a Local> prompt.

Introduction Protocols
1 - 5
1.3 Protocols
A network protocol is a method of communicating over the Ethernet.
Each protocol specifies a certain arrangement of data in the Ethernet
packets, and provides different services for its users. The MSS supports
the following protocols:
• TCP/IP
Support includes Telnet, Rlogin, UDP, and DNS. The Telnet
terminal protocol, supported on most UNIX systems, is an easy-
to-use interface that creates terminal connections to any network
host supporting Telnet. Rlogin is a protocol that allows users to
initiate a TCP/IP login session. UDP (User Datagram Protocol) is
a connectionless protocol that results in smaller packet headers,
no session overhead, and the ability to send to multiple hosts.
The MSS also supports the use of Domain Name Servers (DNS),
allowing a network nameserver to translate text node names into
numeric IP addresses.
The MSS also implements basic Simple Network Management
Protocol (SNMP) functionality. SNMP commands enable users,
usually system administrators, to get information from and
control other nodes on a local area network (LAN), and respond
to queries from other network hosts. The MSS allows
configuration of one community name with read/write access.
• IPX/ SPX (NetWare)
The MSS provides IPX/SPX access to the serial device from
NetWare and any other IPX/SPX nodes. It allows users to
download system files from NetWare hosts and log into the MSS
via NetWare for remote configuration.
The MSS supports all four NetWare frame types: Ethernet v2,
Native mode, 802.2, and 802.2 SNAP.
• Local Area Transport (LAT)
LAT is a protocol developed by Digital Equipment Corporation
(DEC) for local network connections and is supported on most
DEC operating systems. The MSS provides logins to remote hosts
and host-initiated connections, as well as access to the MSS serial
port from LAT hosts.

Software Introduction
1 - 6
1.4 Software
The CD-ROM shipped with the MSS contains operational software. It
also contains EZWebCon software which can be used to configure the
unit.
The MSS is equipped with Flash ROM, so it is not necessary to download
software each time the unit boots. Software must only be reloaded if there
is a problem with the Flash ROM, or if a new software version is released.
1.5 Configuration
Each MSS has a unique name and network address printed on its
underside. The name is based on the MSS Ethernet address and is
referred to in the manual as MSS_xxxxxx . The xxxxxx string represents
the last six digits of the MSS Ethernet address. Be sure to note the
Ethernet address before configuring the unit.
When using IPX or LAT, it is possible to power up the MSS and have it
work properly with no additional configuration required. TCP/IP users
must give the unit an IP address.
NOTE: For more information about methods used to configure an IP
address, see page 3-1.
Lantronix has provided EZWebCon software to help users install and
configure the MSS. It is also possible to configure the MSS settings by
logging into it over a network via Telnet or Rlogin. See Chapter 3, Getting
Started , for more information.
Additionally, the MSS can be configured to download a configuration file
containing boot commands from a NetWare or TCP/IP host at boot time.
See the Change Startup command in the MSS Reference Manual on the
CD-ROM for more information.

Installation MSS485Components
2 - 1
2 - Installation
This chapter covers the installation of the MSS in an Ethernet network
and the attachment of RS-485 devices and a serial console. Basic
knowledge of networking installation is assumed. Read this section
completely before continuing.
2.1 MSS485 Components
The MSS485 front panel has a screw terminal block and an RJ45 port for
an RS-485 serial connection, as well as an RS-232 DB9 console port.
Figure 2-1: MSS485 Front Panel
The screw terminal block and RJ45 connector are wired in parallel. Only
one of these ports can be used at a time.
The MSS485 rear panel has an RJ45 Ethernet connector, a reset button,
and a power connector.
Figure 2-2: MSS485 Rear Panel
Console
DB9 Console Port
Screw Terminal Block RJ45 Port
(RS-485) (RS-485) (RS-232)
10BaseT 6V DC
Reset
Power ConnectorReset ButtonRJ45 Ethernet Port

MSS485 Components Installation
2 - 2
NOTE: When the reset button is pressed and held during the power up and
boot procedures, the MSS returns to its factory default configuration.
Four LEDs are located on the top of the unit. The first LED is a Power
indicator, and should remain green while the MSS is plugged in. The
second is a network Link indicator, and should remain green while the
MSS is connected properly to a 10BASE-T network. The remaining two
LEDs indicate network ( OK ) and serial port ( Serial ) activity. They will
blink off, yellow, green, or red depending on the current activity.
Figure 2-3: MSS485 Top Panel Showing LEDs
NOTE: Although a red LED during boot mode usually signals an error, red
LED patterns are part of the normal operation of the MSS and are not
necessarily indicative of errors or dangerous operation.
The top of the MSS485 also contains an oval-shaped hole in the lower left
corner. The hole accommodates a screwdriver, which is needed to attach
cabling wires to the screw terminal block.
Eight DIP switches are located on the bottom of the MSS485, along with a
label that shows how to configure them. DIP switch settings will be
explained in step 5 of the installation instructions (see page 2-5).
MSS485
RS-485 Serial Server
POWER
LINK
OK
SERIAL
6VDC
10BASE-T RESET
SERIAL CONSOLE
SHLD
TXA
TXB
RXB
RXA
SHLD
POWER
LINK
OK
SERIAL
LEDs

Installation Installation
2 - 3
Figure 2-4: MSS485 Bottom Label Showing DIP Switches
2.2 Installation
Figure 2-5: MSS Network Layout
1. Select a location.
The MSS should be positioned close to the device(s) it will be
servicing but out of the way of everyday activity. Since powering
down the unit will terminate any active sessions, it may be
desirable to place the server in a location secure from user access.
Also be aware of the unit’s environmental operating limits and
cabling limits. See Appendix D for details.
Switch Group Functions
2 Wire 485
4 Wire 485
4 Wire 485 Termination
2 Wire 485 Termination
No Termination
2 or 4 Wire 485 RX Biasing
No RX Biasing
Ground Shield
Float Shield
6
8
7
45
23
1
23
1674 58
MSS485
Ethernet
Bank of RS-485-compliant Devices
Ethernet
Hub

Installation Installation
2 - 4
2. Connect the MSS to an RS485 network.
The MSS is designed to connect to any RS485-based serial
device using either the screw terminal block connector (as
shown in Figure 2-6) or the RJ45 connector. Do not connect
wires to both ports simultaneously.
Figure 2-6: Connecting Wire to Screw Terminal Block
NOTE: Lantronix recommends the use of shielded twisted pair cabling for
RS-485 serial connections. To ensure that data wires are connected
properly see RS-485 Networking Overview on page 1-2 and
Appendix C, Pinouts.
Whenconnecting yourRS-485 networkto the MSSvia thescrew
terminal block, you may have to connect from 2 to 6 wires
depending upon the desired MSS usage mode. Do not over-
tighten the screws; only light pressure is necessary.
NOTE: If you would like to change your RS-485 connection at a later time, be
sure to power down the unit before changing cables or DIP switch
settings.
3. Connect the MSS to the Ethernet.
The MSS can be connected to a 10BASE-T Ethernet network.
Connect a 10BASE-T twisted-pair Ethernet cable to the RJ45
connector on the back of the MSS.
4. Connect a terminal to the MSS DB9 console port, if desired.
The terminal will allow you to view commands as you
configure the MSS. It will also display operational and error
messages so that you can monitor the unit.
Screwdriver
Wire

Installation Installation
2 - 5
NOTE: The DB9 console port parameters are 9600 baud, 8 data bits character
size, no parity, and one stop bit.
5. Set the eight DIP switches on the bottom of the unit to correspond
with your network. Choose one option from each of the following
functional groupings, and be sure not to mix two-wire and four-
wire mode settings. (See Figure 2-4 on page 2-3 for DIP switch
locations.)
NOTE: Any DIP switch configuration not described here could render your MSS
inoperable. Be sure to follow these instructions carefully.
A. Switches 1 through 3 control wire mode. For more information
on wire modes, see
RS-485 Networking Overview on page 1-2.
For two-wire mode, set switches 1 through 3 to the On
position. For four-wire mode, set switches 1 through 3 to the
Off position.
B. Switches 4 and 5 control termination. RS-485 networks should
only be terminated at the extreme ends.
For termination in two-wire mode, set switch 4 to the On
position and switch 5 to the Off position. For termination in
four-wire mode, set both switches to the On position. To
disable termination, set both switches to the Off position.
C. Switches 6 and 7 control RX (receive) biasing. Biasing makes
sure that there is a valid idle signal when no units are
transmitting, but may not be needed on your network.
To enable biasing, set both switches to the On position. To
disable biasing, set both switches to the Off position.
NOTE: The MSS biasing value is 470 ohms in series with a 0.01 uF capacitor.
D. Switch 8 controls grounding of the shielding. RS-485 serial
cabling should generally have one device providing ground.
For a grounded shield, set switch 8 to the On position. For a
floating shield (no ground), set switch 8 to the Off position.

Installation Installation
2 - 6
6. Provide power to the MSS.
Attach one end of the power cable to the MSS and plug the other
end into a wall outlet. There is no power switch on the MSS;
power will come on automatically when the unit is plugged in.
At this point, there is power to the server, so be sure to use
appropriate care when handling the unit.
NOTE: Ensure that you are using the MSS six volt power supply. The
Lantronix EPS1, EPS2, and LRS2 units have a power supply that
looks similar to the MSS power supply, but is a different voltage.
Using the wrong power supply with the MSS will damage the MSS.
Checkto see ifthePower and LinkLEDson the frontofthe server
light. If not, unplug the server and check the power supply, then
check the Ethernet connection and plug the server in again. If the
LEDs still do not light, refer to Appendix B, Troubleshooting .
2.2.1 Power-up Diagnostics
The MSS boot-up procedure consists of three steps. During normal
operation, the boot process requires approximately 30 seconds to
complete.
1. The MSS runs through a set of power-up diagnostics for
approximately five seconds. The Power LED should remain
solid green; the OK and Serial LEDs should show varying
patterns corresponding to the test being run.
NOTE: The Power and Link LEDs should be solid green if the unit is plugged
in and there is a valid connection to a 10BASE-T network.
2. The MSS tries to obtain TCP/IP configuration information via
BOOTP and RARP. This procedure takes approximately 20
seconds if no hosts answer the request. During this step, the OK
LED blinks green approximately three times per second, and
occasionally yellow as packets are sent and received.
NOTE: For more information on BOOTP and RARP, refer to your operating
system’s documentation.
3. The MSS determines if the code in the Flash ROMs is valid. If so,
it loads the code and begins normal execution. This step takes
approximately five seconds.

Installation IsItWorking?
2 - 7
When the unit is running normally, the OK LED blinks green once every
two seconds. If data is being transmitted on the Ethernet port, the OK
LED blinks yellow. The Serial LED blinks red when characters are
transmitted through the serial port, green when characters are received,
and yellow when characters are both transmitted and received.
2.3 Is It Working?
If the MSS appears to be working and the unit is connected to the
network, there are four ways to confirm that it is working correctly:
• If there is a terminal attached, press the Return key and log in.
If you are able to log in, the server is running normally.
• If an IP address has been configured for the MSS (see IP
Address Configuration
on page 3-1), ping the MSS from a TCP/
IP host.
Figure 2-7: Pinging the MSS
• Perform a test using the Test command. See the Commands
chapter in the MSS Reference Manual on CD-ROM for more
information.
When you are satisfied that the MSS is working properly, proceed to
Chapter 3, Getting Started . If the server does not boot properly, see
Appendix B, Troubleshooting .
unix% ping 192.0.1.233

Getting Started
3 - 1
3 - Getting Started
This chapter covers all of the steps needed to get the MSS on-line and
working. There are three basic methods used to log into the MSS and
begin configuration.
1. Incoming (Remote) Logins: EZWebCon is the preferred method of
login and configuration for TCP/IP and IPX users. For TCP/IP and
LAT users, other remote login options are available (see Telnet on
page 3-4).
2. Serial Port Logins: Users can connect a terminal directly to the
console port, log in, and use the command line interface to configure
the unit.
3. Remote Console Logins: TCP/IP users can make a Telnet connection
to the remote console port, port 7000.
It is important to consider the following points before logging into and
configuring the MSS:
• The MSS IP address must be configured before any TCP/IP
functionality is available (see
IP Address Configuration on page
3-2).
• Connecting a terminal to the console port or logging into the
remote console port does not automatically create privileged
user status. You must use the Set Privileged command to
configure the unit (see Privileged Password on page 4-1).
• The remote console port is password protected (see System
Passwords on page 4-1).
• Only one person at a time may be logged into the remote
console port, regardless of the protocol being used. This
eliminates the possibility of several people simultaneously
attempting to configure the MSS.
• Remote console logins cannot be disabled. The system manager
should always be able to access the unit.
• Only one terminal may be connected to the MSS485 DB-9
console port.