Appendix

How To

Enable RFC 2217 in programs using pySerial.

Patch the code where the serial.Serial is instantiated. Replace it with:

try:
    s = serial.serial_for_url(...)
except AttributeError:
    s = serial.Serial(...)

Assuming the application already stores port names as strings that’s all that is required. The user just needs a way to change the port setting of your application to an rfc2217:// URL (e.g. by editing a configuration file, GUI dialog etc.).

Please note that this enables all URL types supported by pySerial and that those involving the network are unencrypted and not protected against eavesdropping.

Test your setup.

Is the device not working as expected? Maybe it’s time to check the connection before proceeding. Miniterm from the Examples can be used to open the serial port and do some basic tests.

To test cables, connecting RX to TX (loop back) and typing some characters in Miniterm is a simple test. When the characters are displayed on the screen, then at least RX and TX work (they still could be swapped though).

FAQ

Example works in Miniterm but not in script.

The RTS and DTR lines are switched when the port is opened. This may cause some processing or reset on the connected device. In such a cases an immediately following call to write() may not be received by the device.

A delay after opening the port, before the first write(), is recommended in this situation. E.g. a time.sleep(1)

Application works when .py file is run, but fails when packaged (py2exe etc.)

py2exe and similar packaging programs scan the sources for import statements and create a list of modules that they package. pySerial may create two issues with that:

• implementations for other modules are found. On Windows, it’s safe to exclude ‘serialposix’, ‘serialjava’ and ‘serialcli’ as these are not used.
• serial.serial_for_url() does a dynamic lookup of protocol handlers at runtime. If this function is used, the desired handlers have to be included manually (e.g. ‘serial.urlhandler.protocol_socket’, ‘serial.urlhandler.protocol_rfc2217’, etc.). This can be done either with the “includes” option in setup.py or by a dummy import in one of the packaged modules.

User supplied URL handlers

serial.serial_for_url() can be used to access “virtual” serial ports identified by an URL scheme. E.g. for the RFC 2217: rfc2217:://.

Custom URL handlers can be added by extending the module search path in serial.protocol_handler_packages. This is possible starting from pySerial V2.6.

Related software

com0com - http://com0com.sourceforge.net/

Provides virtual serial ports for Windows.

License

Copyright (C) 2001-2013 Chris Liechti <cliechti(at)gmx.net>; All Rights Reserved.

This is the Python license. In short, you can use this product in commercial and non-commercial applications, modify it, redistribute it. A notification to the author when you use and/or modify it is welcome.

TERMS AND CONDITIONS FOR ACCESSING OR OTHERWISE USING THIS SOFTWARE

LICENSE AGREEMENT

1. This LICENSE AGREEMENT is between the copyright holder of this product, and the Individual or Organization (“Licensee”) accessing and otherwise using this product in source or binary form and its associated documentation.
2. Subject to the terms and conditions of this License Agreement, the copyright holder hereby grants Licensee a nonexclusive, royalty-free, world-wide license to reproduce, analyze, test, perform and/or display publicly, prepare derivative works, distribute, and otherwise use this product alone or in any derivative version, provided, however, that copyright holders License Agreement and copyright holders notice of copyright are retained in this product alone or in any derivative version prepared by Licensee.
3. In the event Licensee prepares a derivative work that is based on or incorporates this product or any part thereof, and wants to make the derivative work available to others as provided herein, then Licensee hereby agrees to include in any such work a brief summary of the changes made to this product.
4. The copyright holder is making this product available to Licensee on an “AS IS” basis. THE COPYRIGHT HOLDER MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED. BY WAY OF EXAMPLE, BUT NOT LIMITATION, THE COPYRIGHT HOLDER MAKES NO AND DISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF THIS PRODUCT WILL NOT INFRINGE ANY THIRD PARTY RIGHTS.
5. THE COPYRIGHT HOLDER SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF THIS PRODUCT FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS A RESULT OF MODIFYING, DISTRIBUTING, OR OTHERWISE USING THIS PRODUCT, OR ANY DERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF.
6. This License Agreement will automatically terminate upon a material breach of its terms and conditions.
7. Nothing in this License Agreement shall be deemed to create any relationship of agency, partnership, or joint venture between the copyright holder and Licensee. This License Agreement does not grant permission to use trademarks or trade names from the copyright holder in a trademark sense to endorse or promote products or services of Licensee, or any third party.
8. By copying, installing or otherwise using this product, Licensee agrees to be bound by the terms and conditions of this License Agreement.