RS232 Bit Rate Converter User Manual for model RS003 by Adam Pierce
[email protected] last revised 12-Nov-2009
Table of Contents How it Works........................................................................................................................................2 Configuration........................................................................................................................................3 Using Microsoft Hyper Terminal.........................................................................................................5 Specifications.......................................................................................................................................7 Pin Description.....................................................................................................................................8 Document Revision History.................................................................................................................9
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Page 1 of 9
How it Works The RS232 Bit Rate Converter is a signal processing device which can simultaneously receive and transmit RS232 data in two directions. It has been designed to interface between two RS232 devices which are normally unable to communicate because they operate at different speeds from each other. If the transmitting device is slower than the receiving device, the RS232 Bit Rate Converter sends bytes at the faster speed as soon they are received. This may have implications if the receiving device is sensitive to RS232 BREAK conditions. Effectively a BREAK will now be inserted between each transmitted character. This should not affect most equipment.
If the transmitting device is faster than the receiving device, the RS232 Bit Rate Converter sends the data as quickly as it can and also has a 7 kilobyte memory buffer to store incoming data until it can be processed by the receiving device. This has implications if the transmitting device is sending many kilobytes of uninterrupted data, once the memory buffer is full, bytes will be lost from the data stream.
Each port can be individually configured with a different number of data bits, stop bits etc.
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Page 2 of 9
Configuration To configure the RS232 Rate Converter, you will need a serial terminal such as HyperTerminal (Windows) or GtkTerm (Linux) to connect to the device. Once configured, the settings are stored in the RS232 Rate Converter's internal Flash memory. Connect your PC to PORT A on the RS232 Rate Converter using a standard “straight through” modem cable. Start your terminal software and set it to 9600, no parity, 8 data bits and 1 stop bit (9600,n,8,1). Then use a thin object such as a toothpick or pencil to press the recessed programming button on the top panel of the RS232 Rate Converter. All four lights should illuminate to indicate you are in configuration mode. You will also see the following text appear on your terminal:
Choose which port you would like to configure by pressing A or B on your keyboard. You will then see the menu shown on the next page...
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As you can see by the screen-shot, the parameters you can change are:
Parameter Baud Rate Parity Data Bits Stop Bits
Possible Values from 46 up to 115200 NONE, ODD, EVEN, MARK or SPACE 5, 6, 7 or 8 1, 1.5 or 2
When entering the baud rate, if the rate you enter is not available, it will choose the nearest available rate and display that. Once you have made your changes, press M to return to the main menu. From the main menu, you can choose S to save your new settings. If you would like to discard your changes and revert to your previous settings do not press S, just remove power from the RS232 Rate Converter and start it up again. NOTE: If you change the settings of port A to something other than 9600,n,8,1, the change will not actually occur until you leave configuration mode. Configuration mode always communicates at 9600,n,8,1. Pressing Q will leave configuration mode and return to normal operation.
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Page 4 of 9
Using Microsoft Hyper Terminal Here is a step-by-step guide for setting up Microsoft Hyper Terminal to use for configuring the RS232 Bit Rate Converter. Hyper Terminal comes installed by default in most versions of Windows. First launch Hyper Terminal by clicking START → All Programs → Accessories → Communications → HyperTerminal The following window will appear. Type a name for your connection:
Next select the port you will be using. I have selected COM1 in this example but yours may be different, especially if you are using a USB to RS232 adapter.
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Page 5 of 9
Make sure the port settings match the ones shown here. In particular, make sure you set the Flow control to “None” or you might not be able to communicate with the Rate Converter.
You should now be able to configure your Rate Converter as described above on page 3.
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Page 6 of 9
Specifications Supply voltage
4.8V - 12V DC, centre positive
Operating Current
Between 25mA and 120mA depending on speed and load.
Operating Temperature
0°C to 70°C
Number of RS232 ports
2
RS232 Bit Rates
Most rates from 46 bits per second to 115200 bits per second.
RS232 Parity options
none, odd, even, mark or space
RS232 Data bits
5, 6, 7 or 8
RS232 Stop bits
1, 1.5 or 2
Hardware handshaking
Not supported
XON/XOFF
Not supported
Buffer Memory
7168 bytes
Indicators
Receive and Transmit LED indicator for each port
RS232 Input voltage
Mark: < 0.6V Space: > 2.4V
RS232 Output voltage
Mark: -5.4V Space: +5.4V
Physical Dimensions
66mm x 66mm x 28mm
Weight
80g
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Page 7 of 9
Pin Description Port A (female connector) Pin number
Direction
1
Description Not connected
2
To PC
Transmitted Data
3
From PC
Received data
4
Not connected
5
Signal ground
6
Not connected
7
Not connected
8
Not connected
9
Not connected
Port B (male connector)
Pin number
Direction
1
Description Not connected
2
From PC
Received Data
3
To PC
Transmitted data
4
Not connected
5
Signal ground
6
Not connected
7
Not connected
8
Not connected
9
Not connected
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Document Revision History 5 Oct 2008
Completed first edition (HTML format).
6 Apr 2009
Converted to PDF format. Added technical specifications.
23 Sep 2009
Added step-by-step guide for configuration using Hyper Terminal. Added pinout table.
15 Oct 2009
Revised for new model RS003. Updated product photo.
12 Nov 2009
Corrected some spelling errors and layout issues. Added more detail to the “How it works” page.
RS232 Bit Rate Converter User Manual – see http://serialgadget.com/ for updates
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