In an FM two-way radio system, CTCSS encoder levels are usually set for 15% of system deviation. The tones are usually referred to as sub-audible tones. The tone is transmitted at a low level simultaneously with the voice.
#How to use ctcss tone kenwood tk 880 code
Radio transmitters using CTCSS always transmit their own tone code whenever the transmit button is pressed. Radios equipped with the "Busy Channel Lockout" feature will prevent transmitting in this case. The more groups that share a single frequency and the more frequently they transmit, the more likely that this accidental interference will occur. The two simultaneous transmissions could interfere with each other-resulting in one or both not being understood. Meanwhile, a pizza delivery driver-not hearing any transmissions-assumes that the frequency is clear and calls their dispatch office. For example, in the above situation, a landscaper might be communicating with another landscaper. They may erroneously assume that the frequency is idle and then transmit at the same time as another user, thus interfering with the other group's transmissions. The disadvantage of using CTCSS in shared frequencies is that users cannot hear transmissions from other groups. In dense two-way radio environments, many separate groups may co-exist on a single radio channel. Note that in the example above there are only two co-channel users. This is supposed to reduce missed messages and the distraction of unnecessary radio chatter for the other users. With CTCSS and a different tone for each group, radios hear only the activity from their own group. The landscapers have to listen to the pizza shop and the pizza shop has to hear about landscape activity. Conventional radios without CTCSS would hear all transmissions from both groups. The tones are not actually below the range of human hearing, but are poorly reproduced by most communications-grade speakers and in any event are usually filtered out before being sent to the speaker or headphone.Īs a simple example, suppose a two-way radio frequency is shared by a pizza delivery service and a landscape maintenance service.
The CTCSS feature also does not offer any security.Ī receiver with just a carrier or noise squelch does not suppress any sufficiently strong signal in CTCSS mode it unmutes only when the signal also carries the correct sub-audible audio tone. All users with different CTCSS tones on the same channel are still transmitting on the identical radio frequency, and their transmissions interfere with each other however the interference is masked under most (but not all) conditions. It is sometimes referred to as a sub-channel, but this is a misnomer because no additional channels are created. Where more than one group of users is on the same radio frequency (called co-channel users), CTCSS circuitry mutes those users who are using a different CTCSS tone or no CTCSS. It does this by adding a low frequency audio tone to the voice.
(See squelch.) It is sometimes referred to as tone squelch. Although these lines are available from CN1-CN7 and it's possible to cross-reference those and tack-solder to them, instead of risking toasting the runs I'd spend the $20 and buy the KCT-19.In telecommunications, Continuous Tone-Coded Squelch System or CTCSS is one type of in-band signaling that is used to reduce the annoyance of listening to other users on a shared two-way radio communications channel. What you really need if you want to hook up a tone panel is the KCT-19 option cable that gives you Mic Hi, Mic E, PTT, DET OUT, COR, 13.8V, HOOK, etc.
#How to use ctcss tone kenwood tk 880 serial
I only have a V2 manual (and I don't seem to have a V1 version), but most of them are identical.Īs you can see, they are all serial and logic points for accessory decoder and scrambler boards made by 3rd party vendors. The pins you are looking at are for Kenwood supported accessory boards.
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