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     Having a burning question? Chances are some one might have asked the same question before. Here is a collection of frequently asked questions to our tech support through e-mail and phone calls. Of course, if you don't see your question answered here, please send us a note or call our tech support hotline at 1.800.653.9970.

General Questions

General Technical Support Questions

Digital Products

Analog Products

Serial Products

Software Questions

Sub Device Ids

Mean Time Between Failures Information


General Questions:

Do you have products that support the 3.3 volt PCI bus specification?

How would I go about using your products in a laptop?

    While we do not currently make any products that support typical laptop bus protocols (PC Card, PCMCIA), we have found a way to use our PCIe products with a laptop by utilizing an expansion system.
    Our PCIe products (including PCIe to PMC adapter) with the PCIe expansion system mentioned below, should work with a Laptop. We have tested it in our lab and it worked fine.
    Cabled PCI Express for Desktops and Laptops: http://www.magma.com/expressbox-1
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Since upgrading to a Windows 64 bit OS, I seem to be having problems with transferring data.

    Some General Standards products have a bus interface chip that uses 32 bit registers for DMA transfers. If your system has more than 4GB of RAM and you are using a 64 bit version of Windows, there is the possibility that a DMA buffer address could be beyond the 4GB limit of the 32 bit registers. Try temporarily reducing the amount of RAM in the system to 4GB or less. If your transfers now work properly, contact General Standards Technical Support to find out about software work-arounds for this issue. Generally, this has not been an issue on Linux operating systems.
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I am looking for MTBF (mean time between failures) information for your products.

How do I contact technical support and when should I call?

    If, after reading the manual and the relevant FAQ help files for your product, you are still experiencing difficulties installing or using your product, call the technical support hotline. Please try to be at your computer with your manual, software, and product. Technical support can be reached at 1.800.653.9970, 8:00AM-5:00PM CST, Monday through Friday, or email your questions to a member of our tech support team!.
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My design is almost perfect, but I really need to change one small thing. Can you do this for me?

I have to write my own application, do you have any sample programs to help?

    Yes! We can supply sample programs that contain commented code that you would need to include with your application to make calls to our driver. For DOS users there are also several types of sample programs.
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What is PC/104 Express?

General Technical Support Questions:

Do your cards come with a factory warranty? If so, what procedures need to be followed in an event of failure, and who would we need to contact for repair services.

    Boards have a one-year parts/labor warranty. GSC may choose to repair or replace a board at its option. Turnaround is typically one to ten working days. Customer pays for shipment to GSC; GSC pays for return freight with same delay. GSC disclaims any warranty for any particular application and is not responsible for any consequential damages. Out of warranty repair is available at one-third list price for the board; replacement price is one-half list price.For repairs, RMAs or returns, please contact a member of our returns team!
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How do I determine what board I have?

    There is a label on the card that indicates the model and serial number followed by a Revision letter located on the board as part of the copper or silkscreen.
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I've lost my Manual. How can I get another?

My system has a PCI Bridge and the General Standards card will be located downstream. Is their any special configuration I need to be aware of?

Are the PC104-Plus cards assigned specific communication signals?

    PCI Device and Interrupt Assignment for PC104-Plus In the PC104-Plus stacking configuration, each of up to four modules is assigned specific communication signals as described in Paragraph 3.2.2 of the PC/104-Plus specification, Version 1.2. Because of the stack-through nature of the bus, slot-specific signals are duplicated for each plug-in module, and include IDSEL[3:0], CLK[3:0], REQ*[2:0], GNT*[2:0] and INT[A-D].

    In this product, the device identification and interrupt lines are controlled by the position of the octal switch located at one edge of the module (Figure 1.1-1). The exact relationship or mapping of switch positions and slot-specific signals may vary among manufacturers of PC104-Plus motherboards. Keep in mind; some manufacturers may assign one of these slot-specific signals (slots) to a device located on the processor board, limiting the number of modules that can be stacked thus, a conflict with one of the devices in the stack can occur. Should this happen, refer to the motherboard documentation on how to resolve it.

My original card is working and the new card is not functioning properly. What may be the problem?

    Verify that you have not set reserved bits. General Standards utilizes reserved bits to add new features as required by customers.

Can you give me the specifications of the CPU board that would support your cards?

    We have tested the following CPU boards:

    A. Winsystems, EBCTX Plus
    B. Versa Logic, VSBC8

How can I change IRQs assigned to my PCI communication board?

    Because the BIOS allocates resources for the PCI bus, IRQs can only be changed by moving your adapter to a different PCI slot. If you have only one free IRQs or no IRQs available the IRQs assigned to the PCI adapter may not change.
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I have an older VME card and was wondering if you had a replacement on another form factor?

    We have newer cards on PCI, PMC and cPCI that can replace most VME boards manufactured by General Standards Corporation.
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What is RS-232?

    Probably the most widely used communication standard is RS-232. This implementation has been defined and revised several times and is often referred to as RS-232 or EIA-232. The most common implementation of RS-232 is on a standard 25 pin D sub connector, although the IBM PC computer defined the RS-232 port on a 9 pin D sub connector. Both implementations are in wide spread use. RS-232 is capable of operating at data rates up to 20 Kbps / 50 ft. The absolute maximum data rate may vary due to line conditions and cable lengths. RS-232 often operates at 38.4 Kbps over very short distances. The voltage levels defined by RS-232 range from -12 to +12 volts. RS-232 is a single ended interface, meaning that a single electrical signal is compared to a common signal (ground) to determine binary logic states. A voltage of +12 volts (usually +3 to +10 volts) represents a binary 0 and -12 volts (-3 to -10 volts) denotes a binary 1.
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What is RS-422?

    The RS-422 specification defines the electrical characteristics of balanced voltage digital interface circuits. RS-422 is a differential interface that defines voltage levels and driver / receiver electrical specifications. On a differential interface, logic levels are defined by the difference in voltage between a pair of outputs or inputs. In contrast, a single ended interface, for example RS-232, defines the logic levels as the difference in voltage between a single signal and a common ground connection. Differential interfaces are typically more immune to noise or voltage spikes that may occur on the communication lines. Differential interfaces also have greater drive capabilities that allow for longer cable lengths. RS-422 is rated up to 10 Megabits per second and can have cabling 4000 feet long. RS-422 also defines driver and receiver electrical characteristics that will allow 1 driver and up to 32 receivers on the line at once. RS-422 signal levels range from 0 to +5 volts. RS-422 does not define a physical connector.
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What is RS-485?

    RS-485 is backwardly compatible with RS-422; however and is optimized for multi-drop applications. The output of the RS-422/485 driver is capable of being Active (enabled) or Tri-State (disabled). This capability allows multiple ports to be connected in a multi-drop bus and selectively polled. RS-485 allows cable lengths up to 4000 feet and data rates up to 10 Megabits per second. The signal levels for RS-485 are the same as those defined by RS-422. RS-485 has electrical characteristics that allow for 32 drivers and 32 receivers to be connected to one line. This interface is ideal for multi-drop or network environments. RS-485 tri-state driver (not dual-state) will allow the electrical presence of the driver to be removed from the line. The driver is in a tri-state or high impedance condition when this occurs. Only one driver may be active at a time and the other driver(s) must be tri-stated. RS-485 does not define a physical connector.
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Will standard off the shelf cables work with my RS-422/485 Board?

     No. These cables are made with RS-232 in mind and do not conform to the pin-out for RS422-485. It is best to contact us for cabling information. 
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What is the maximum distance I can run my cable with your RS-232 cards and RS-422/485 cards?

    The specification for RS-232 calls for a maximum distance of 50 feet at 20Kbps and the RS-422/485 specification calls for a maximum of 5000 feet at 9600Bps. Data rates are a function of the distance of the cable. The shorter the cable length the higher the data rate that can achieved.



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How do you provide uniform cooling at various altitudes?

To provide uniform cooling at various altitudes, approximately the same mass-flow of air is required regardless of atmospheric pressure. This means supplying twice the volumetric air flow at one-half atmosphere, 10-times at 1/10 atmosphere, etc.

Interconductor Spacing:
The arcing threshold between conductors drops with reduced atmospheric pressure.
Conformal coating is usually the remedy for this. Conformal coating is expected to raise the arcing threshold such that the board should work up to 80,000 feet. The connector will not be conformal coated; however, it probably has a voltage rating of over 100 Volts at sea level.

Digital Products:

I would like to perform a loop-back data test on my HPDI32 to validate the card is working properly. I write a data pattern to the FIFO, but when I read back from the FIFO, I don't get my data. Am I doing something wrong?

    It is certainly possible to do a loop-back test on your HPDI32! A little information about how the on board FIFOs work is warranted here. There are effectively two 32 bit wide, 32K deep FIFOs (for the -256K model) on the card, one for transmit data and one for receive data. The logic on the card looks for an access to local offset 0x18 and checks the Read/Write line from the PCI interface. If the R/W line indicates a write is taking place, the logic puts that data in the transmit FIFO. If the R/W line indicates that a read is taking place, the logic reads a word from the receive FIFO. This confuses a lot of people because they want to write to the FIFOs at offset 0x18, then do a read of 0x18 and don't understand why they don't get back the data they wrote. Their data is actually still sitting in the TX FIFO. Here is a way to loop the data from transmit to receive, which involves a just a few steps:

    1) Make sure any external cables that could drive the cable are disconnected,
    2) Put test data in the transmit FIFO,
    3) Enable transmit in the Board Control Register,
    4) Enable receive in the Board Control Register,
    5) Set the Start_Transmit bit in the board control register (wait for this bit to clear itself before proceeding to read) and
    6) Read the now transferred data from the receive FIFO (again at offset 0x18).
    That's it! You should now be able to test your loop-back data from the receive FIFO.
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Who supplies cable clocks and when?

    When the HPDI32 card is set to be a transmitter, the card supplies a transmit clock on pins 1 and 2 of the cable connector (from the factory, this transmit clock is installed at 20Mhz) that is synchronous with the data output. When the HPDI32 is in receive mode, the card expects to receive a clock on pins 1 and 2 of the cable connector. The HPDI32 uses this clock to register data. If no clock is provided, no data will be saved to the receive FIFO.
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The factory supplied transmit clock is the wrong speed for my application. What are my options?

    Usually accommodations can be made when a card is ordered to obtain a different transmit clock frequency. Simply let your sales person know the frequency you need, and we will give you a special part number to order with. If you have already received your cards and need to change the installed clock, see the Hardware Configuration section of the User's Manual for detailed pin-out information on the clock chip. This chip can be changed in the field to accommodate many different frequencies. Maximum reliable speed for the RS485 version of the card is 26Mhz, where the maximum speed for the PECL version of the 40Mhz, assuming a reasonable length cable.
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I really just need a simple way to save data into my HPDI32 card. Is there a way to implement a simple interface utilizing a "data valid" type signal to clock my data in?

    Yes! The easiest way to implement a simple interface is to tie the Status Valid line (pins 7 and 8 on the cable) to a logic low and tie the Frame Valid line (pins 3 and 4 on the cable) to a logic high. Then the Line Valid signal (pins 5 and 6 on the cable) becomes functionally a "data valid" signal, as when this line is high, a data word is clocked into the card on each clock cycle. Alternatively, you may tie Line Valid and Frame Valid together to act as a data valid when these lines are pulled high. Do make sure to tie Status Valid low, though, since if this line floats, it can cause erroneous data collection from the cable.
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I am trying to program the FIFO almost full and almost empty flags. I write a value to these registers, but when I write/read data to/from the FIFOs, the flags don't change where they should.

    In order for the value in the programmable FIFO registers to be loaded , you need to perform a FIFO reset after writing these registers. This is accomplished be setting the FIFO reset bits(s) in the board control register. Be careful not to do a board reset, as this will cause the FIFO programmable almost registers to be cleared.
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Analog Products:


What are the advantages of high-resolution sigma-delta ADCs?

    The advantages of high-resolution ADCs include inherent antialiasing and high linearity. Static accuracy and broadband noise however, are not significantly improved by the Sigma-Delta (or Delta-Sigma) architecture. In fact, some Delta-Sigma ADC products exhibit huge offset and gain errors of several percent or more, but are considered entirely suitable for acoustic applications.

    For example, the data sheet (attached) for the newly released 24-Bit 256KSPS AD7768 converter from Analog Devices indicates a broadband SINAD of 107dB (17.5 bits ENOB). The supporting input analog networks contribute typically 3-5 dB of additional noise, for a further ENOB reduction of approximately 0.5-0.8 bits.

    Minimizing aliasing however, simplifies the improvement of dynamic range through post filtering. For example, a converter with a sample rate of 200KSPS and a useable bandwidth of 80kHz might exhibit a typical SINAD of 105dB (17 bits ENOB). By post filtering the output of the converter to limit the bandwidth to, say 5kHz would decrease the noise by a factor of approximately 4, for a SINAD increase of 12dB to 117dB (or an ENOB increase to 19 bits). <back to top>

What is a simple, graphical way I can view data received from one of your A/D boards?

    To look at the data captured from several of our A/D board products is a more general purpose software tool called ScopeDSP. It does a good job of displaying sample data from a previously saved file. It also shows you signal statistics (RMS values, etc) and can do FFT transformations. Read more about ScopeDSP
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How do I set the effective sampling rate on the PMC66-14HSAI4 board?

    The PMC66-14HSAI4 board's effective sampling rates are a function of the register values of the four board parameters: Nvco, Nref, Ndiv-clk, and Ndec. Please see section 3.4.3 of the 14HSAI4 manual for a detailed description of how this works. The general problem is to find values for these parameters that produce a solution to the equations in that section of the manual that yields the user's desired sampling rate - or if it's not possible to get an exact solution - to find a solution that minimizes the sampling rate error - so as to get as close as possible to the user's desired sampling rate. A computer program was written to allow users to quickly find the best solutions for any desired sampling rate from 1.000 KHz to 50.000 MHz. The program is called 14HSAI4setup. Click here to download
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What's required to install the 14HSAI4setup program?

    Download 14HSAI4setup.zip to a computer running Windows 2000 or later. Unzip the zip archive into any convenient location. This will unzip into a new folder named "14HSAI4setup". Within that folder will be an executable file named "14HSAI4setup.exe" and some support files that are needed by the program. Double-click the icon to run the program. A shortcut that points to this program can be added to the desktop if desired. There is no installation. This program may be removed from the computer by deleting the 14HSAI4setup folder, and any shortcuts to it you've created. (A version of this program that works under Linux is available upon request.)
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How do I use this program?

    Enter the desired effective sampling frequency in Hertz - samples per second. (e.g. 10.002 MHz would be entered as "10002000" - an integer without any decimal point. Enter "0" to terminate the program.) The program will find a solution, but will sometimes show multiple solutions. If several solutions are shown note the Fsample(error) results and choose the best one from among those listed.
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What is the latency of the PCI-ADADIO board?

    As long as the delay is less than 5 milliseconds between conversions, the conversion time is only 5 microseconds. If the time span is greater than 5 milliseconds then the conversion time is 9 microseconds. This is for the 200kHz version of the board.

    ADC sampling can be triggered: (a) software, (b) externally through hardware or (c) by the internal rate generator. For a 200KSPS board, the time from a trigger to when all four channel values are present in the buffer is 5.Ous. If a DMA-read is started immediately after the buffer-empty flag falls
    (i.e.: when the first values appear in the buffer), total time from a trigger through PCI four transfers would be 5.5-6 Ous. System delays (not controlled by the ADADIO) would increase this time.

    The latency does not change until you get down to 160 samples per second, this latency increases to 10.5 to 11.O micro-seconds due to a double-sampling requirement imposed by the ADC at very low sample rates.

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How do I set the sample rate for the PCI 16SDI?

    The answer is almost boundless due to the number of variables but click here to download an excel document that should be of great help.
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How do I "find the board" on the PCI Bus

    The answer is to perform a PCI Configuration Access. You may click here to download a sample function to do a Configuration Access on X86 machine. Click here to download a white paper explaining PCI Bridge Compatibility
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Serial Products:

What is the maximum speed of my Serial Card?

    The maximum data rate is 1 Mbps asynchronous and 10 Mbps synchronous. This number is the result of a mathematical calculation based on the on board oscillator value on the card. Actual maximum data rates may vary depending on cable length, type of driver, operating system overhead, disk activity, etc.
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Where can I obtain a user's manual and product specifications for the Zilog Z16C30 chip used on the Serial I/O boards?

      The Zilog web site has the specification and User's Manual for the Z16C30. The User's Manual covers the serial protocols supported by the Z16C30.To access the Z16C30 User's Manual (.pdf format) just click here. Here you can view, search, or print the User's Manual for the Z16C30.
    To access the Z16C30 Product Specification (.pdf format) just click here .Here you can view, search, or print the Product Specification for the Z16C30.
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I cannot achieve the baud rate needed for my application using the factory installed 20MHz clock. What options are available?

    The oscillator for the baud rate generator is socketed so we can easily accommodate any frequency commonly available.
    Practically all boards so far have been shipped with the 20MHz oscillator since the baud rate generator on the Zilog chip provides a lot of flexibility in baud rate.
    We currently do not charge a premium for installing a special frequency, provided that it is available from stock at a distributor.
    Simply add -nn.nMHz to the model number to specify frequency of the oscillator. For example, for a PMC-SIO4-256K with a 16MHz oscillator for controlling specify PMC-SIO4-256K-16MHz.
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What is the difference between the SIO4BX/SIO8BXS and the SIO4BX/SIO8BXS-SYNC boards?

    This is a high-speed serial card that features the Zilog Z16C30 serial controller chips. This card is best used when the serial protocol will be one of the "industry standards" such as HDLC/SDLC, asynchronous, isochronous, bisync or monosync. The Zilog chips will handle the protocol specific overhead and add/strip extra information from the serial data stream to make it match the requested protocol. This card offers deep FIFO buffers (up to 32KB) to help reduce the risk of data loss at high clock rates. The SIO4BX can run up to 10 Mbits/sec in synchronous protocol modes and 1 Mbit/sec in asynchronous mode with the software selectable transceivers set for differential (RS422/485) mode. Single-ended modes, such as RS232 and RS423, are limited to 230 kbits/sec. Drivers are available for Windows, VxWorks and Linux.

    This is a high-speed synchronous serial card that basically performs simple serial to parallel conversion of data. It does not support the high level protocols like the SIO4BX/Zilog chips and does not add/strip any information to/from the data stream. This card is best used when the customer is using a proprietary serial protocol that can be decoded in software or simply needs to send or receive raw serial data without any of the high level protocol overhead. This card offers deep FIFO buffers (up to 32KB) to help reduce the risk of data loss at high clock rates. The SIO4BX-SYNC can operate at up to 10 Mbits/sec with the software selectable transceivers set for differential (RS422/485) mode. Single-ended modes, such as RS232 and RS423, are limited to 230 kbits/sec. Drivers are available for Windows, VxWorks and Linux.

    Note: The SIO4B and SIO4BX cards are functionally identical except the SIO4BX features software configurable cable transceivers.
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Software Questions:

Sub Device Ids:

Does General Standards provide a means of locating their card on a system bus?

    Yes. Please click here to download a document with subsystem ids listed for all General Standards products.
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Do you have sample windows programs for your cards?

Where can I get the latest Windows drivers?

And as always, if you have an URGENT question, please call 800.653.9970 or 256.880.8787.

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