156 lines
6.7 KiB
Plaintext
156 lines
6.7 KiB
Plaintext
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<meta name="generator" content="HTML Tidy for HTML5 for Apple macOS version 5.8.0">
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<title>JMRI Hardware Support - Keyspan USB adapter</title>
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<meta name="author" content="Bob Jacobsen">
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<meta name="author" content="John Plocher">
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<meta name="keywords" content="Keyspan USB java model railroad JMRI install">
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<h1>Hardware Support: Keyspan USB connections</h1>
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<p>This page describes tests of two USB-to-serial adapters, done circa 2010 using the
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<a href="MS100.shtml">Digitrax MS100</a> LocoNet® interface.</p>
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<p class="important">We strongly recommend to use a better solution to connect a computer to
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a LocoNet, such as the <a href="LocoBufferUSB.shtml">LocoBuffer USB</a> or the <a href=
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"PR3.shtml">Digitrax PR3</a>/<a href="PR4.shtml">PR4</a>.</p>
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<p>The MS100 is a passive level shifter that gets its power from the control leads in the
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RS232 interface. Digitrax has not published a schematic, but Bill Robinson of Team Digital
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has graciously provided a schematic of their level shifter which is thought to be very
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similar.</p>
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<p><img src="./images/LN_to_PC.gif" alt="Sample LocoNet to RS232 Interface Schematic">
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</p>
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<h2>Summary</h2>
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<dl>
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<dt class="left">Keyspan PDA adapter P/N USA-19</dt>
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<dt class="left">Summary: This worked fine.</dt>
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<dd>
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<p>Unfortunately, this adapter is no longer made. We believe that the replacement
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"Keyspan High Speed Serial Adapter" Part# USA-19QW is the same unit.</p>
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<p>We've had a report that this PDA adapter can't work with a LocoBuffer at 57,600 baud.
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There seem to be multiple versions of the adapter, with slightly different model numbers,
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and it could be that some of them will only work at speeds of up to 56,000 baud.</p>
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</dd>
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<dt class="left">Keyspan Dual Serial Adapter P/N USA-28X</dt>
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<dt class="left">Summary: This did not work.</dt>
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<dd>Problems: the USB adapter provides only one control line output, and the serial port
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outputs were only +/- 5V. This was not enough to power the MS100 during receive.</dd>
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</dl>
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<h2>Details</h2>
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<dl>
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<dt class="left">Keyspan PDA adapter P/N USA-19</dt>
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<dt class="left">Summary: This worked fine.</dt>
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<dd>
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<p>This was actually the second USB serial adapter I tried, after the Keyspan Dual Serial
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Adapter (see below). This adapter provides a DB9 male plug, pinout previously available from
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http://www.keyspan.com/products/USB/PDAadapter/docs/mac/html/homepage29.html , Keyspan
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product support page. Note that there are both RTS and DTR outputs; these can be
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separately controlled to provide + and - voltage to the MS100.</p>
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<p>I connected it through a DB9 female to DB25 male adapter cable that I happened to
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have, and the test program was immediately able to communicate with the LocoNet.</p>
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<h3>DB9 female to DB25 male connections</h3>
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<pre>
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DB9 pin DB25 pin
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------- --------
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DCD 1 8
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RxD 2 3
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TxD 3 2
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DTR 4 20
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ground 5 7
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DSR 6 6
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RTS 7 4
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CTS 8 5
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RI 9 22
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</pre>
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<p>Note that I didn't test the level input from the MS100 (DSR, CTS).</p>
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</dd>
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<dt class="left">Keyspan Dual Serial Adapter P/N USA-28X</dt>
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<dt class="left">Summary: This did not work.</dt>
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<dd>
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<p>The initial problem was that the USB adapter provides only one control line output
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( pinout previously on
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http://www.keyspan.com/products/USB/usa28x/docs/swp/aPinOuts.html , the Keyspan product
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support page. This means that the serial port can only provide one of the two + and -
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levels needed for the MS100. Since there are two ports, I build a small adapter to use
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the control line from the second port to provide the other level.</p>
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<p><a href="./images/KeyspanJumper.jpg"><img src="./images/KeyspanJumper-thumb.jpg" alt=
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"Keyspan USA-28X did not function">(click to enlarge)</a>
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</p>
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<p>The second problem was that the serial port outputs were only +/- 5V. This was not
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enough to power the MS100 during receive.</p>
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<p>The following picture shows the transmit data levels from the Keyspan adapter. DC
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levels had similar ranges. This was a large enough swing to drive the LocoNet itself, but
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not to power the receive level shifter in the MS100.</p>
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<p><a href="./images/KeyspanTxD.jpg"><img src="./images/KeyspanTxD-thumb.jpg" alt=
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"Oscilloscope image showing Keyspan USA-28X TxD voltages"> (click to enlarge)</a>
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</p>
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<p>Providing auxiliary +/- 9V power to the MS100, without using the output lines as a
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power source, was not sufficient. The following picture is the received data, nominally
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an RS232 signal of at least +/-6 volts, from the MS100. The received data signal was
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getting up to 6V, marginally OK, but it was not going below ground. The USB serial
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adapter was not reporting any received characters to the Macintosh.</p>
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<p><a href="./images/KeyspanRxD.jpg"><img src="./images/KeyspanRxD-thumb.jpg" alt=
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"Oscilloscope image showing inadequate Keyspan USA-28X RxD voltages"> (click to
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enlarge)</a>
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</p>
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<h3>Hardware & Software used</h3>
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<p>The tests were done with a PowerBook G4 400MHz, Mac OS 9.1. The test program was a
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Java application created with CodeWarrior 4.1.0.3 build 661. This program is available on
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request, see below for address. Java access to the USB serial adapters was via Patrick
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Beard's Macintosh implementation of javax.comm.</p>
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<p>The Digitrax system was a Chief, DT100IR throttle, and various decoders on the layout.
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Traffic from command station, throttle and various auxiliary components (PM4, DS54) was
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available for testing.</p>
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</dd>
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</dl>
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<p>LocoNet® is a registered trademark of <a href="https://www.digitrax.com">Digitrax,
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Inc.</a></p>
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