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Interface 4 wire circuit to radio

Posted: Wed Jun 23, 2004 1:33 pm
by N0RHM
In our E-911 center we have a NAWAS telephone which is used, among other things, as a statewide communications network with the National Weather Service offices in our state. This telephone is hooked up to a 4 wire circuit, 2 receive, 2 transmit. I would like to extend the capabilities of this phone to the alternate 911 centers as well as our EOC. A number of counties are currently broadcasting this traffic over a vhf radio. Some also have the capability transmit and receive with this system. I am looking for some type of remote that will interface the 4 wire circuit to the radio and provide 2 way communications via radio to our alternate locations. I would also need to use Pl or DPL so the interface will not key up with just any transmitter on the frequency. I would appreciate any help in this and thanks in advance.

Posted: Wed Jun 23, 2004 1:50 pm
by wx4cbh
Any good professional communications service shop (Motorola or GE/MA-Com etc) oughta be able to do that in their sleep unless there's a problem with system interface protocols or documentation forbidding such an interface. 4 wire remote panels are pretty commonplace.

Posted: Wed Jun 23, 2004 2:06 pm
by N0RHM
The Motorola shop in this area said it would take a couple of hours of research and wants to charge me $150 for a quote. I have bought many thousands of $$$ of stuff from them and never taken a quote to someone else to beat down prices. I feel kind of screwed.

Posted: Wed Jun 23, 2004 3:33 pm
by wavetar
I think $150 is very reasonable. If you wish it done correctly, you should have no problem with them spending a few hours researching in order to provide you with a solid quote that won't change because something was overlooked/not explained fully.

If their company is anything like most, the fact you've spent money buying product from them was great business for the sales side, but really didn't do much for the service side. The techs need to get paid as well, and competent ones generally aren't cheap.

Todd

Posted: Sat Jun 26, 2004 2:38 pm
by Alan
The price for the quote is reasoable (if anything it sounds low) as this is not a "standard" product. Custom interfaces like this are a one-time thing.

In these days with current purchasing policies where full capability service shops are under cut for the off-the-shelf product, it is only reasonable to charge for the work required to properly investigate and design a solution.

I have seen may instances where we have done this design work for no charge as we were expecting to "get" the buisneess, only to find that our work was used to form the detail of a tender or provide the required details for the customer to do the job themselves.

Posted: Sat Jun 26, 2004 5:31 pm
by Will
Alan, good point.

Posted: Tue Jun 29, 2004 3:43 am
by jayres
You might check with your State Control Point for NAWAS before even attempting this... I recall reading in one of my old NAWAS Manuals at one time that you couldn't even move your terminal (within a building) or perform any modifications to the system without permission from the SCP.... Just something to maybe help you out...


Jon