Communications Speed Comparison
[an error occurred while processing this directive]Introduction
Windows CE offers a variety of methods to communicate and synchronize. I have tested serial communications, Ethernet and Proxim Symphony effective throughputs for copy a 4,011,104 byte file to the HP Jornada 680, Casio E-105 and NEC MobilePro 800 using ActiveSync and the Redirector.
CompactFlash Ethernet Cards
PC Card Ethernet Cards
Proxim Symphony PC Card
Notes: All testing was performed on a Windows 95 Pentium 233 mhz PC with 64 MB of ram on a network with the PC and H/PC or P/PC only. Ping Time is the based on the dos command to ping the H/PC or P/PC. Activesync copy was performed using Windows CE Services 2.2 after synchronization was complete. The redirector copy was done from a shared drive on the PC. The file used to copy was a 4,011,104 byte file (the H/PC Pro Plus Pack install program). The directed link results for the Proxim Symphony card are 100% signal strength, approx 40,000 bytes/sec, 27 packets/sec, 1500 byte packets with transmit latency of 35 msec. The Socket, TDK and Xircom tests were performed with their software installed. The Socket driver had the display function on.
As you can see, users with using Serial Communications at the default 19,200 baud will take over 30 times longer to perform similar tasks to those that use Ethernet or Proxim Symphony regardless of the card used. Surprisingly, the Ethernet Cards all appear to have similar results so purchase decisions should be made on cost and additional features of the card and the driver. I recommend that all users adjust the baud rate of their serial port to 57,600 baud or 115,200 baud based on what works reliably. The process for adjusting the baud rate is described in detail in the Windows CE Services Help (Mobile Devices, Help, Find - Changing the Baud Rate). I anticipate that the IrDA communications times will be identical to the serial port performance listed above. As always, you performance may vary compared to above based on the conditions used for testing and the speed of the equipment.
I was surprised that Ethernet was not faster since it is 10 megabits/sec and only copied at about 120 kbytes/sec. Based on this performance, I do not believe that existing devices would make good packet sniffers. However, Ethernet clearly offers the highest speed access to synchronize and the web for you P/PC or H/PC.
What method of synchronization do you use?
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I tried Copy & Convert using ActiveSync 3.0 on an HP Jornada 680 and Gateway 233Mhz notebook. The Access 2000 database table has 6000 records with 60 fields/record. It is 3.1MB. In 11 hours using a serial 115KB connection it becomes a 4.1MB Pocket Access table. I tried the same C & C using a Socket LP 10MBit PC Card. It took 11 hours cumulative and required two restarts.
There seems to take several orders of magnitute excess time. Just copiing files of this size should take less than an hour using a 115KB serial connection and under a minute or two using a 10MBit ethernet connection.
You guys are doing nice work, but you are "barking up the wrong tree". The way to do all this is save every thing that has any size to a large compact flash. then remove the flash and put in your reader or portable. It then operates at near-RAM speed. I load a 65 megabyte movie file into my E-105's flash card in a minute or two. With excel files--don't convert just save on card. the excel clone reads it directly. I find very few things don't work well this way and you avoid all the problems that are created with cabling and docks et cetera. My suggestion forget cables and just deal with the 1 inch square compact flash. (place most stuff in "my documents" master file on CF)
I use the serial cable for the sync. Now there is a serial to USB cable available at HK. Do you think it will work to connect the sync port to the desktop USB so the transmittion speed will improve? The cost of the cable is only 1/5 of a ethernet CF and with no set up required.
Let me know the result if you can manage to give it a try.
Barnny from Hong Kong
USB performance from HP Jornada 548 is disappointing. The best speeds I managed are:
single file download (explorer cut/paste): 21KBytes/s single file upload (explorer cut/paste): 14KBytes/s activesync backup: 6Kbytes/s
This, from an interface that can manager 100s of Kbytes/second. HP have no answers.
I ran your test with an Hitachi ePlate using a 4.025 meg file and both wired and wireless connections. The wired connection was a 3-Com CF card hooked to a switch, and that one took 0:33. The wireless was an Aironet 340 PC Card connected to a 342 Access Point on the same switch. That one took 0:47 to complete. While the same card gets an 11 meg connection in my laptop it only gets a 1 meg connection when in the ePlate, which must be a driver limitation since we are talking about the wireless portion of the connection rather than the internal portion. Haven't found an explanation.
I have Jornado 545 It's working under the windows ce but I want to palm os program on my jornado.Because Some List Programs Working With Palm os program.That's why I need Changed Program Windwos ce , Palm os Program.How You can help me.? Grettings . Gurkan Ayisigi
anybody out there able to use serial comm to peripheal devices while running a program under a DOS emulator on a jornada 720
I noticed you are missing the Compaq iPAQ 3600 series in your tests. I do mostly contract work, so most of files are relatively small.
I timed the transfer of 4 files - 1 excel and two word docs to my iPAQ via USB --- total size of the transfer - 597kb. Notes on the project, who to contact, etc; the excel files were expense reports and timesheets. The transfer, including conversion, took 42 seconds....... I don't know if that's good or not -- but it's fast enough for me!
Chris, I am searching for a comm port redirector that will allow me to use a network modem from a WinCE Device with a Proxim Notwork card. Any ideas where I should look. Thanks. Mike Richard firstname.lastname@example.org
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