Ground, and you won't see a swinging voltage, a 5k or so pullup On some receivers the COS uses a relay and that has a dry contact to Swings high or low to give either a + voltage or ground with the The COS signal can be either a set of relay contacts or a voltage that If the repeater does not have aĬontroller, the COS simply does the function of turning on and off the If the controller is set up for Carrier Squelch (CSQ) it then turns onĪnd off the repeater transmitter. That the receiver squelch is open, and that there is a signal there. Switch is to tell the repeater controller, if the repeater has one, So you ask how does it work and what's the purpose, and where can Iįind this COS on a receiver? The function of the carrier operated Nowadays most of the repeaters are solid state, except for aįew which have tubes in the final amplifier, so now we call it COS or Repeaters had tubes in them, and all circuit switching was done by This is going back to the early days of repeaters in which all the The Carrier Operated Switch (COS) used to be called COR. So What's The COR or COS? - Ric Sohl KK5RIC
Yaesu has enter the arena with their proprietary System Fusion. Vocoder technology merged with packet technology and D-Star took the VHF and UHF bands by storm with the help of a single vendor and the JARL (Japan Amateur Radio League). With the advent of faster computer processors and vocoder technology, analog voice moved into the digital age, both on the HF bands and on VHF and higher bands. Over the years, the digital ham’s interests may have included CW, RTTY, then Packet (AX.25), and a whole host of mainstream and experimental digital modes, and even WiFi (802.11). The digital ham started at the same humble beginning, CW over spark gap. The spark gap transmitter gave way to frequency selective transmitters and receivers using CW CW gave way to AM AM was largely pushed aside by SSB FM became the mode of choice for most on the VHF and shorter wavelengths. Public service, and to leave the hobby better than when you entered. Learning new technologies, experimentation, meeting new friends, The most important thing about the hobby of Amateur Radio is to enjoy Perhaps I should get a cheapy Motorola M120 from eBay and PTT radio him to clarify! :)Īmateur Radio Future - Network Radio - Zello PTT Apps? 5,452 viewsĪmateur Radio Guideto Digital Mobile Radio (DMR) You can google AdaFruit or SparkFun for their very good newbie friendly logical level converter tutorials. For Rpi the usual get around is to use a logical level converter to step down the ham radio trasnsceiver's possibly 5V signals to 3V3 signals which are now compatible with Rpi. On the other hand, 5V Arduino Uno should have no problems, because they are designed to entertain 5V logical level signals. In other words, Rpi might be damaged if the transceiver's PTT/COS pins are directly connected to Rpi GPIO.
Rpi GPIO pins runs on 3V3 logic and are not 5V logic signal level tolerant. The PTT and COS pins may carry 5V TTL logic signals. I found one thing confusing is the the COS pin shares with PL, perhaps that causes confusion.Īctually I think what the OP needs is the simple program I already briefly described in the question. Actually the OP is not talking about the ideas, but the PTT and COS pins, as illustrated below. I googled a bit and found the question is easier than I thought. Similarly, GPIO In2 is connected to GPIO Out1.įor each loop Function 1 checks if GPIO pin In1 is low, if yes, Function 1 will make GPIO pin Out1 low, so that Function 2 will Let us call the two functions Function 1 and Function 2, and they are doing similar things as briefly described below.įunction 1 takes care of two Rpi GPIO pins, input pin GPIO In1 is connected (through a 4k7 resistor) to output pin GPIO pin Out2, which is I have a python program running a loop of two functions "talking" to each other.
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