DSchmidt Technologies Ordering Information and Q/A


Hello, thank you for considering ordering my products! Here's some ordering and background information about DSchmidt Technologies.


DSchmidt Technologies is winding down. DTMF products are no longer popular, and everyday life is getting more and more busy.
For my existing business customers, you can still order what you need - contact us.

About DSchmidt Technologies

DSchmidt Technologies has been in business since November 1995 and is my second "employer". My regular 9-5 job is working as the Manufacturing Test Manager for an infrared camera company. My official work hours there are Monday through Friday, 7:30am until 5:30pm but my typical day is 6am - 7pm

Between the hours of 6:00am until typically 8pm , I am not at DSchmidt Technologies to receive orders, phone calls, or fill orders. By the time I receive your order, UPS, Fedex, US Postal Service, DHL, etc are all closed. This prevents me from addressing your questions over the phone, plus prevents me from shipping any orders the same day. This is why any orders placed for items in stock will not ship until the next business day. This is also why the best way to reach me with any questions is via email at info2@dschmidt.com)

Payment Information

Returns accepted up to 45days from shipment date.
All returns due to no error on our part are subject to a 10% restocking fee.

Shipping Information

Commonly Asked Questions

Ordering Questions

Contact Information

    I have questions. What is the best way to reach you?
    I do not have access to my phone messaging machine at my main place of employment. I also do not place phone calls at my regular employer to conduct my side business activities. I am however able to access my business email account during my breaks and lunchtime. Therefore the best way to reach me to ask questions is via email. You can reach me at info2@dschmidt.com

General Product Information

    What do I get when I order a product from you?
    With the exception of the electronic parts only items, all products come with an owner's manual. This manual will cover the capabilities, power requirements, operation, and if necessary, how to program the device.

    Do I get the microcontroller source code for the product I purchase?
    No. All microcontrollers used in my products are programmed with the code protection turned on. In other words, they are protected from being read. The source code for all my products are not available for sale either.

    What is the warranty period for a product I purchase?
    With the exception of the electronic parts only items, all products come with a 90 day warranty. If during this time the item fails due to workmanship or parts failure the product will be replaced or repaired at my option. Products which are abused (incorrect voltage supply or polarity used, mechanical damage, modified in any way) are not covered.

Specific Product Information
DTMF Products

    I need an RS232 to DTMF Encoder. Do you make one?
    No. At this time there is no RS232 to DTMF encoder or any DTMF encoder in the works.

    I want to decode DTMF tones from a tape How can I do this? I've only had a handful of customers that have been able to successfully decode DTMF tones that were recorded onto tape. Tape players do not faithfully reproduce DTMF tones. They frequency shift, frequency skew, distort and introduce noise to the recorded DTMF tones. All this combined creates an audio signal that is unuseable. I DO NOT RECOMMEND MY DTMF PRODUCTS IN TAPE PLAYER APPLICATIONS!!

    I want to hook your DTMF decoder to the phone line directly. How can I do this?
    First, some background on telephone lines. Telephone lines are floating relative to earth ground. So, grounding either side of the phone line intentionally or accidentally is a no no. You'll end up causing interference on your phone line and the phone company will think you have something wrong with your line. You might wonder how a phone line can be grounded accidentally. Remember that your computer most likely has a three prong power cord. This third ground pin ties your computer, and all its connected peripherals and ports to earth ground. Plug my DTMF decoders into your serial port and you have now just tied the audio input connector to earth ground.

    The correct way to hookup to the phone line is to use an isolation transformer, also called a 600:600 transformer or a modem transformer, and a DC blocking capacitor. This electrically isolates the phone line. Click here for a sample schematic.

    My office uses digital phone lines (Rolm, Lucent, etc). Will your product work?
    No. The digital phone lines in your office do not carry analog signals. In other words, the sounds you hear in the earpiece are not the same as what you would hear if you plugged in a regular phone. Unless the outlet you wish to use in your office is wired for an analog phone line (like for a modem or a fax for instance), my DTMF products will not work.

    Can I plug a microphone into your decoder directly? Will it work?
    No. The audio input for my decoders has no amplification. A microphone's output requires amplification to raise its output to a level sufficient for my decoders to work.

    How do I retrieve stored tones? Do you supply software for my PC to download stored tones?
    No, there is no software provided. In the days before the Internet, there were a lot of "terminal" programs out there that would let you communicate with a modem connected to your serial port. Unfortunately today, with PPP and SLIP connections to get you on the internet, nobody needs to know how to talk to a modem or serial port anymore and terminal programs are not as prevalent anymore. The program I use is Procomm Plus for Windows. I don't know if it is available anymore.

    To download stored tones to your PC, you need to have a free serial port to plug my decoder into (usually COM1 or COM2). If you use Windows 95/98/NT, there is already a built in terminal communications program called Hyperterminal. It is located in the Start - Accessories - Communications folder. Using this program, you can download the stored tones by setting up this program to read from the serial port you have my device plugged into. Use the help menu in Hyperterminal to setup the correct communications settings.

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