Since many years this website has been the home for my CRC source code library. Recently I decided to move the routines together with recent updates and additions to their own home. The CRC library can therefore now be found at www.libcrc.org.
Nov. 11 2010
Browser Header Checker
With each request to a web-server, a browser send a number of header lines which give the web-server information about the client configuration. These header lines are normally not seen by web users, but can now be made visible with the new on-line Browser Header Checker page on this website.
Feb. 16 2010
IPTables firewall page
A firewall is a software or hardware implementation of a filter which tries to block undesired traffic over a computer network, while allowing all other traffic. Linux has a built in firewall system based on the iptables filter rules in the kernel. This page explains how this firewall can be configured to protect a Linux based computer or network.
Jan 17. 2010
HDMI interface page
One of the new popular digital interfaces is the HDMI interface. It is able to transport both audio and video signals at a high rate between a large number of devices. A page has been written with the most common properties of this interface. The HDMI interface is not only used on computers, but also on set-top boxes, VCRs, game consoles etc. It has rapidly replaced the VGA and DVI interface in computer applications.
Jan 11. 2010
Time synchronization with Garmin GPS
GPS receivers are mostly used for position calculation, but they can also be an excellent source for accurate time. I have connected a Garmin GPS to one of my servers and its clock now runs with an absolute error of just a few microseconds. The page which describes the process and how you can do it yourself is now available on this site.
Jan 4. 2010
USB cable length page
For many users of USB, it is not always clear what the maximum cable length is they can use for a specific purpose. A new page about the USB cable length explains why the maximum lengths are how they are, which physical property limits them and how longer distances can be bridged with USB.
Jan 3. 2010
Bluetooth interface page
Most communication interfaces described on this website use cables for the data transfer. Nowadays many communications are however performed through the ether. One of the best known wireless interfaces is Bluetooth which was developed to connect small battery operated devices to all kind of equipment. I have now dedicated a page to the Bluetooth interface.
Jan 2. 2010
CRC connectors page
The USB standard started with only two types of connectors, but with the introduction of smaller devices and more functionality the number of available USB connectors has significantly increased. A new page now summarizes all USB connectors with their use and properties.
Dec 1. 2009
CRC calculation page with Ajax
One of the most visited and loaded pages is the CRC calculation page. In the original setup, every touch of the Calculate button caused a full reload of the page. The page has now been rewritten in such a way that only the changing table with CRC values is reloaded from the server. This decreases the response time for the user and lowers server load.
Dec 26. 2008
DIY electronics pages
Besides computer interfacing and software development, I have done a lot of electronics development in the past. Many of these projects are small and suitable for a larger audience. I have therefore decided to make the most interesting projects available on-line.
Apr 8. 2008
VoIP introduction page
Computer technology evolves and what once was leading edge technology is now a legacy from other times. To prevent this site from becoming a legacy of the past I am currently working on a series of pages describing new protocols and technologies in communications. Today the first page about Voice over IP has been released.
Aug 22. 2006
Start of German version of website
Today is one of the special days of this website. The first page in the German language went life. It is the page about RS232 cables. Writing in the local language of visitors opens a whole new world. The rest of the site will be converted to German in the coming time. There is however no fixed schedule.
Jul 12. 2006
Tutorial on RS232 to USB converters
Many visitors are confused by the word serial which is both used for the RS232 port, and the USB port on the computer. I often receive emails asking how to connect these two ports. This can however not be done directly, a special converter and driver software is needed to make RS232 working over an USB line. I have written a new page about the specific problems arising from these converters.
Jun 14. 2006
Unitronics RJ11 cabling system added
The PLC manufacturer Unitronics uses an interesting serial connection system with RJ11 connectors. The system is symmetrical to allow for direct interconnection between PLCs with both RS232 and RS485. Pinouts for this interface have been added to this website. Also common layout for interconnection and programming cables are shown.
Mar 16. 2006
RS232 software shop opened
Many of the visitors of this website are not only seeking cable solutions for their problems, but also software. I have now added an RS232 software shop, with links to several communication software and libraries. All software can be bought and downloaded directly.
Nov 24. 2005
Free counter removed
Since 1998, I have used the free Netstat Basic counter script on the site to keep track of the most important pages on this site. I have never had any problems with this counter. Unfortunately, at September 1st this year, the free service has been sold to a German ad company which relaunched the service under the name Webstats4u. Within a few days this company added a popup ad script to the counter code, resulting in unwanted SPAM popping up when some of the pages on this site were loaded. Because I am not visiting my site very often, it took some time for me to realize that the ads were generated by the counter code on my pages. After I discovered this I immediately removed all offensive code from my sites.
I would like to apologize for the inconvenience that users may have felt the last months because of these unaccepted advertising tactics.
Aug 5. 2005
Modbus interface description
There are a handful of interfacing standards in industrial communications. The Modbus interface—already developed in 1979—is the most widely used interface. PLC manufacturer Modicon created this standard and then allowed every other manufacturer to implement the interface in their equipment. Today I put a tutorial about Modbus on the website.
May 21. 2005
Description of Yost standard
The Yost standard—defined by Dave Yost in 1987—is one of the best ways to connect RS232 over RJ45. I have added a page
with the description and pictures of the needed conversion adapters to the website.
May 7. 2005
Added RS-485 information page
The already 40 years existing communication standard RS-232 is more and more replaced by the more versatile USB standard. But for scientific and industrial communication, RS-232’s nephew RS-485 plays a more important role than ever. Therefore I have added an RS-485 information page to the website. Plans are to cover also RS-422 and RS-423 in the near future.
January 11. 2005
Added on-line CRC calculation form
Until recently most of the site has been written in plain HTML code to be as compatible as possible with all sorts of browsers. Because of the current possibility to do scripting at the hosts side with PHP, more intelligent functionality can be added without compromising this choice. Therefore now an on-line CRC calculation page has been added which calculates the CRC16, CRC32, and CRC-CCITT values for a given string without the need for java scripting enabled at the user’s side.
January 3. 2005
Speed increase main menu
The loading time of the main menu has been increased by combining all small menu buttons into two large image files. Especially for users connected over a slow line, or far away from the image server this speed increase will be noticeable.
January 3. 2005
Moved large files to second server
Let me first wish you the best for 2005.
Because of the ever increasing traffic to the website, a second web-server is now operational for the large files like pictures and datasheets. This split in servers will probably provide enough bandwidth capacity for the coming years. If you encounter any problems as the result of this move, please contact me.
December 27. 2004
RS232 serial printer cable page rewritten
The information about serial printer cables has been completely rewritten. An explanation why printer cables differ from normal null modem cables has been added. New is also the information of some specials. The information has been moved from the general RS232 cable page to a new dedicated page on the site.
December 26. 2004
RS232 spy/monitor cable information added
Until now, only brief information was available on the site about sniffing RS232 communication between two devices. The information has now moved to a new page where solutions for both half duplex and full duplex communication are discussed. Also new in the wiring diagrams is the loop-back of the handshake signals at the spy computers side. This prevents some software from blocking the input data.
December 24. 2004
DEC MMJ information added
Until now, only very limited space on the site was used for the DECconnect cabling system with MMJ plugs. As this information becomes more difficult to find on the web I have written a new page designated to all the cables and adapters used by DEC in the past.
December 20. 2004
Lammert Bies’ new website is released to the web. The information of the previous site has been transferred and where necessary updated. New is the menu which makes it possible to chose every page directly. Many visitors had problems to find the needed information right away and therefore the site map was the most visited page of the site 🙁 Also new is the quick links menu at the left which points to interesting and relevant other pages.