In the Denver area, there are wo primary Taxi services, Yellow Cab and Metro Taxi, (Taxicabs U.S.A.) I am curious. How can the calls be decoded? Freqs: Yellow has a couple, 152.39, 152.36, and Metro has 452.100, 452.200 and there are a few others? Anyone know how to do this? Please point me in the right direction....
DDS Digital Dispatch System Decoding
- Thread starter ka0txw
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EMS-1
Member
Yellow Cab of Birmingham and The Old Veteran Cab Co. had frequencies of similar like 152.330 and 152.420 etc. and the suddenly they disappeared....Digital? Who knows?. But you cannot hear thm anymore regardless. Carl
D
DaveNF2G
Guest
Cab companies in my area tend to use LTR systems operated by radio shops.
ka0txw,
Are you sure that they are using a digital system? I can think of two cab companies around me that used frequencies right around the ones you listed and they were using plain old voice.
Even if you cant decode them, you probably wont be missing out on much, because its pretty mundane traffic. I listened to the one company here for a couple minutes and it got boring pretty quickly.....
Are you sure that they are using a digital system? I can think of two cab companies around me that used frequencies right around the ones you listed and they were using plain old voice.
Even if you cant decode them, you probably wont be missing out on much, because its pretty mundane traffic. I listened to the one company here for a couple minutes and it got boring pretty quickly.....
nd5y
Member
Digital Dispatch http://www.digital-dispatch.com is a company that makes mobile data terminals. Most of the taxi companies in a lot of areas like Dallas-Fort Worth are using DDS systems . It does a lot of stuff like provide text messaging and AVL data. It is also a secure encrypted system so that your credit card info can be sent over the air. You can't decode it.
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Dds
Okay,
I got it. In Denver, ONLY the credit card authorization routine is encrypted. DDS deploys QPSK64 Quadrature Phase Shift Keying, with a constellation of 64 "fields" (If you will). I finally built a device that works with a Motorola M100 mobile radio. The discriminator tap for the receiver is right on the back of the radio. A nice plus!!
I am now receiving the calls from the output stream (152.330), It's weird though. It appears that there's some "multiplexing" going on. The baseband data appears to enter
the 16550 at 9600k, what gives? The research continues. It's the thrill of the hobby.
And yes... sometimes I post twice! When you are rolling down the road while typing the keyboard gets bounced around alot.
hi hi 73 de KA0TXW, "Golden Screwdriver"
Okay,
I got it. In Denver, ONLY the credit card authorization routine is encrypted. DDS deploys QPSK64 Quadrature Phase Shift Keying, with a constellation of 64 "fields" (If you will). I finally built a device that works with a Motorola M100 mobile radio. The discriminator tap for the receiver is right on the back of the radio. A nice plus!!
I am now receiving the calls from the output stream (152.330), It's weird though. It appears that there's some "multiplexing" going on. The baseband data appears to enter
the 16550 at 9600k, what gives? The research continues. It's the thrill of the hobby.
And yes... sometimes I post twice! When you are rolling down the road while typing the keyboard gets bounced around alot.
hi hi 73 de KA0TXW, "Golden Screwdriver"
AZScanner
Member
What software are you using to decode this? In a previous life I used to work for SuperShuttle - they also used the DDS system. It was pretty neat, I'd love to be able to decode it just for grins.
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