FieldServer FS-8704-11 User Manual

A Sierra Monitor Company

Driver Manual

(Supplement to the FieldServer Instruction Manual)

FS-8704-11 Telnet

APPLICABILITY & EFFECTIVITY

Effective for all systems manufactured after May 1, 2001

Driver Version 1.00b

Document revision Rev 1

FS-8704-11 Telnet Driver Manual Index

Table of Contents

1.

INTRODUCTION................................................................................................................. 1

2. CONFIGURING THE TELNET DRIVER.............................................................................2

3. OPTIONAL CONFIGURATION ITEMS ..............................................................................3

3.1. AUTOCONNECT PORT ..................................................................................................... 3

3.2. AUTOCONNECT MODE ....................................................................................................3

3.3. LOGIN ............................................................................................................................ 3

3.4. TIMEOUT ........................................................................................................................3

4. USING THE SERIAL PORT CAPTURE ............................................................................. 4

4.1. MANUAL SERIAL PORT CAPTURE ....................................................................................4

4.2. AUTOCONNECT SERIAL PORT CAPTURE AND MULTIPLE TELNET SESSIONS ......................5

5. SETTING THE LINEFEED OPTIONS ................................................................................5

6. SETTING THE ECHO OPTION ..........................................................................................5

7. SETTING THE TAB OPTION .............................................................................................5

8. SETTING THE VERBOSE OPTION ................................................................................... 5

9. RUNNING SERIAL PROTOCOLS OVER TELNET USING VIRTUAL PORTS ................. 6

10. LIMITATIONS .....................................................................................................................6

11. REVISION HISTORY ..........................................................................................................6

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldserver.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

FS-8704-11 Telnet Driver Manual Page 1 of 6

1. Introduction

The Telnet driver allows a user to connect to the FieldServer using a standard Telnet client
(such as the Windows Telnet client). A command prompt is provided which allows the user to
request specific driver functions. Presently, the following functions are implemented:

1. help / ?: lists available commands and states their functions.

2. port: this allows the user to take over a serial port.

3. linefeed: this allows the user to control sending and receiving of line feeds in association
with carriage returns.

4. echo: allows the user to determine whether characters typed into the Telnet terminal
should be echoed by the FieldServer.

5. verbose: allows the user to determine the level of detail of diagnostic messages.

6. tab: allows the user to select substitution of received tab characters by space characters

The driver will support up to 5 concurrent Telnet sessions but will not allow two sessions to
control the same serial port.

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldserver.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

FS-8704-11 Telnet Driver Manual Page 2 of 6

2. Configuring the Telnet driver

To use the Telnet driver, the configuration (*.csv) file in use must resemble the following example:

// Set up common information

FieldServer
Title
Telnet Server

Adapters
Adapter, Protocol, Username, Password, autoconnect_port, autoconnect_mode, session_timeout
N1, TLN, Joe, Secret, R1, Text, 60s

Adapters
Adapter,protocol
N1,SMT

// Set up the TLN Server side

Ports
Port Baud Parity
R1 9600 None
R2 9600 None
P1 9600 None
P2 9600 None
// examples of virtual comports
VS1 - ­VC1 - -

Note that the Telnet Driver will only be able to connect to ports that have been declared in the configuration file.

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldserver.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

FS-8704-11 Telnet Driver Manual Page 3 of 6

3. Optional Configuration Items

3.1. Autoconnect Port

If a port is specified in the autoconnect port field, the first Telnet session to connect to the
FieldServer will immediately be connected to the specified port (see Using Serial Port
Capture below). Any further simultaneous Telnet sessions will see the usual command
prompt.

3.2. Autoconnect Mode

Two modes, Text and Binary, are available for use with Autoconnect Ports. Text mode is
optimized for manual use when using Telnet to communicate with a serial device that
presents a user interface (such as a text driven menu screen). This allows the user to
customize how tabs and linefeeds are sent and received. Also, the user can quit a port
capture by hitting Ctrl-C.

If the intention is to run a binary serial protocol over a Telnet connection, the Binary mode
must be specified. This does not modify the data stream in any way.

3.3. Login

If desired, a username and password can be set in the csv file to restrict access to all
functions modifying the operation of the Telnet driver, e.g. port, linefeed, tab. The Login
command will prompt the user for the username and password before these commands may
be used.

3.4. Timeout

A timeout can be set to close the Telnet session and its TCP connection after the specified
period of inactivity. Specify the timeout in seconds in the session_timeout field.

It is important to specify the session_timeout if the FieldServer is mainly used as a serial
protocol client continually communicating with the device. Under these circumstances, if a
Telnet session captures the serial port, the protocol driver is put on hold until the port is
released. If the user forgets to release the port and leaves the Telnet session connected, the
protocol driver on the FieldServer can never resume communications with the device, and
the bridge data is never updated. If the session_timeout is set, then a period of inactivity will
cause the port to be released and the Telnet session to be closed, so that the protocol driver
can resume its communication activity.

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldserver.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

FS-8704-11 Telnet Driver Manual Page 4 of 6

4. Using the Serial Port Capture

4.1. Manual Serial Port Capture

• Once the FieldServer is up and running, connect to it using its IP address.

• Type port <Enter>

• When prompted, enter the name of the port to be captured (e.g. P8 <Enter>). The

driver will check if the desired port has been initialized by a “port” statement in the
configuration file. If the port has been initialized and is available, the driver will wait
for any current polls to finish, and will then print “Connected” to indicate that the port
is now under the control of the Telnet client. If a device is connected to the captured
serial port, you can now communicate with it as if you had a direct serial connection.

• To disconnect the port from the Telnet session, press Ctrl-C. This will also work

while the driver is still waiting for an active poll to complete.

• To terminate the Telnet session, close the Telnet client.

Notes:

1. If a port has been manually captured in one Telnet session, it will not be available to

any other Telnet sessions. Other sessions attempting to capture the port will be
returned to the command prompt with an error message. To release a port, the
connected Telnet session must be disconnected.

2. Capturing a port makes the port unavailable to any protocol driver on the FieldServer

that might have been communicating with the device. Refer to the comments on
session_timeout above on how to prevent an indefinite lockout if a Telnet session
with a port capture is forgotten on.

3. A Serial connection needs to be specified before defining the Telnet connection

(which has autoconnect_port) or else the FieldServer will give system error.

Example

Not Correct:

Connections
Adapter, Protocol, Autoconnect_port
N1, TLN, P1

Correct:

Connections
Adapter, Baud, Timeout, Protocol
P1, 9600, 10s, -

Connections
Adapter, Protocol, Autoconnect_port
N1, TLN, P1

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldserver.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

FS-8704-11 Telnet Driver Manual Page 5 of 6

4.2. Autoconnect Serial Port Capture and Multiple Telnet Sessions

If an autoconnect port has been specified, a new Telnet session to the FieldServer will
automatically be connected to the specified port (in binary or text mode as specified). This
raises a potential conflict if there is already an existing session autoconnected to that port.
The FieldServer resolves this by terminating the original Telnet session, so that new session
is not locked out.

In text mode it is possible to quit out of a port autoconnect by hitting Ctrl-C; this session then
receives a Telnet command prompt. If this is done, the next new Telnet connection that is
made to the FieldServer will connect to the autoconnect port without affecting the first
session.

5. Setting the Linefeed Options

Linefeed sending refers to the transmission of linefeeds generated by the Telnet user to a
comport he may be connected to.
Linefeed receiving refers to the option of inserting a linefeed into the data stream received
from a comport whenever a carriage return has been received.

• Once the FieldServer is up and running, connect to it using its IP address.

• Type linefeed <Enter>

• When prompted, enter the desired state for linefeed sending and receiving (on/off

<Enter>).

• To keep the current setting, just hit <Enter>.

6. Setting the Echo Option

This option determines whether or not the FieldServer echoes characters typed into a Telnet
terminal.

• At the Telnet prompt, type echo <Enter>

• When prompted, enter the desired setting (on/off <Enter>).

• To keep the current setting, just hit <Enter>.

7. Setting the Tab Option

This option determines whether or not the FieldServer replaces incoming tab characters with
spaces during port capture.

• At the Telnet prompt, type tab <Enter>

• When prompted, enter the desired setting (on/off <Enter>).

• To keep the current setting, just hit <Enter>.

8. Setting the Verbose Option

This option determines the level of detail of diagnostic messages printed to the Telnet client.
There are three levels: 0 – not verbose; 1 – medium verbose; 2 – verbose.

• At the Telnet prompt, type verbose <Enter>

• When prompted, enter the desired setting (0/1/2 <Enter>).

• To keep the current setting, just hit <Enter>.

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldserver.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]

FS-8704-11 Telnet Driver Manual Page 6 of 6

9. Running Serial Protocols over Telnet using Virtual Ports

The Telnet driver can be used to run serial protocols over TCP. To connect the Telnet driver to
a serial driver, use virtual comports. Virtual comports are software emulations of real comports,
and are connected in pairs. These connected pairs are ports VC1 and VS1, VC2 and VS2, VC3
and VS3, VC4 and VS4, and VC5 and VS5. Anything written to the port VCx will be received at
the port VSx, and vice versa. Note that autoconnect mode does not modify the data passing
through in any way; it overrides any linefeed or tab options that might have been set.

Serial ports on two FieldServers may be connected over TCP in this way, using a Telnet client
on one end and a Telnet server on the other. The client is configured to connect to the server
using Telnet, and both client and server autoconnect to the desired serial ports on the
respective FieldServers. The two serial ports are then transparently linked.

10. Limitations

The Telnet driver will only capture ports that have been specified in the configuration file
used by the FieldServer. It will use the specified port parameters (baud rate, start/data/stop
bits, parity), or FieldServer defaults where these have not been specified.

11. Revision History

Date

09/05/02 1.00 0 JCE JCE-Created Document
09/06/02 1.00 1 MF MF-Reformatted Document
7/23/03 1.00 2 JD Releasing

Driver
Version

Document
Revision

Resp Comment

FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldserver.com

Tel: [phone] Fax: [phone] Toll_Free: 888-509-1970 email: [e-mail]