Ctcss continuous tone controlled squelch system is a method of allowing different groups of radio users to use the same channel frequency without. The standard frequencies available for assignment are. Tone selection is programmable through the use of solder pad jumpers. The continuous tone coded squelch system, commonly referred to as ctcss, has been in used in the land mobile radio arena from the late 1960s. In case of dispute, the reference shall be the printing on etsi printers of the pdf version kept on a specific network drive. I was hoping someone could help me identify where to install the unit. It only relieves you from listening to unwanted conversations.
As soon as the correct frequency is obtained, the squelch will open on the transceiver with ctcss decode. Scanning is used for hands off monitoring of your favorite frequencies. The baofeng uv5r is a great cheap little radio, but its notoriously difficult to use, with poor documentation. For the best results, you should compare ctcss frequency information from your thirdparty radio with the information in this table. Split tones transmitting and receiving different ctcss tones or dcs codes. Tone decoder require a certain number of cycles to decode. Ctcss codes are functions that reject undesired signals on your channel. These tones are transmitted with the voice audio at all times during the. Also known by various trade names such as private line pl, channel guard and quiet channel. Ctcss pl tone frequencies larkfield amateur radio club. Chirp tone programming examples the screen shot of chirp below contains examples of various ctcss and dcs modes. Hi all, i have not had any luck using the manual for the ft221 in installing the ss64 ctcss tone board unit.
Motorolas privacy codes are a form of ctcss tone codes. The on4dst ctcss encoder is a miniature ctcss tone generator. For completeness i have included a table containing the available tone frequencies and a cross reference to what others name them. Talk on channel 1 and change only the privacy code. A ctcss tone is a continuous tonecoded squelch system, something brought over to the hobby from pmr. Try entering channel 1 on frs frequency into a modern scanner. Ctcss dcs ctcss continuous tone coded squelch system or digital coded squelch. Low current draw, about 7 ma standby and 20 ma with the led lit, depending on logic sourced and its input impedance. Ctcss is usable only for fm signals and is usually associated with both amateur and commercial twoway repeaters. The national interoperability field operations guide nifog is a. Freq mhz watts m gmrsfrs frequency cheat sheet do not transmit on frequencies that you are not authorized to use.
Your gxt250 can transmit a call tone for a fixed length of time. Arduino ctcss decoder for our local repeater on0wv, i was looking out for a possibility to decode the assigned ctcss tone sent from friends, and next to that, detect ctcss from signals sent to other repeaters in the surrounding area, on same frequency sent from foes. This subaudible tonecontrol system was originally developed by. Then you return to vfo and set up the tx frequency with its tone mode and ctcss frequency. You will notice too the tone code as well will change for each privacy code. A ctcss tone is subaudible and is selectable from among 42 tone frequencies. In more practical terms, it is a tone that you cant hear that is added to your transmission so that you can access a distant repeater. Continuous tonecoded squelch system the radioreference wiki. Amherst walkie talkie centre ctcss radio tone frequencies and. Instead of providing almost 10 separate dedicated decoders, i explored the possibilities to handle this by one arduino board. This plan is an ideal mod for old fm tx, without tone sqelch.
Ctcss encoder decoder board by masters communications. You will hear a call only when you receive a signal that contains a matching ctcss tone or dcs code. Transmit a 2 second carrier with a ctcss tone of 74. Nov 30, 2016 in telecommunications, continuous tone coded squelch system or ctcss is a circuit that is used to reduce the annoyance of listening to other users on a shared twoway radio communications channel. Channel number frequency pmr radio ctcss frequency list sub. Setting ctcss tone frequency the tone frequency may be selected from 50 frequencies from 67.
The tone squelch function does not function in digital mode. Ctcss uses a subaudible tone transmitted on the signal of the transmitter trying to access the repeater. Tone codes used on frsgmrsmurs radios radioreference. Amherst walkie talkie centre ctcss radio tone frequencies and ctcss numbers crossreference ctcss continuous tone controlled squelch system is a method of allowing different groups of radio users to use the same channel frequency without overhearing each others messages. Very handy little device if you do much with two way radio or want to find out the tone and frequency a radio is. Below is the terminology used by different commercial companies for ctcss. Attach a dummy load to the transmitter and key down the transmitter which turning r1.
Amherst walkie talkie centre ctcss radio tone frequencies. Depending on the subaudible tone frequency selected using the programming inputs, as well as if that particular tone frequency is present in the audio input, the rx decode output pin 15 will go to a logic level one for a valid tone decode. The ctcss code frequency or tone in hz is the assigned audio frequency. Ctcss dcs cross tone ctcss you may sometimes want to hear calls only from specific persons. Channel number frequency pmr radio ctcss frequency list. This link is listed in our web site directory since friday mar 4 2016, and till today gmrs frs frequencies and ctcss has been. It is known by a number of different trade names such as private line pl by motorola, channel guard cg by general electric and generically as tone squelch it is a use of subaudible tones that are transmitted along with the speech portion of. You may discover it while youre puzzling over the fact that a particular repeater seems deaf to your signals. Digital coded squelch dcs is another application which allows you to.
The acscert communications plan uses the motorola frs channel numbering standard. The amateur radio unit can operate either as an fm transponder or aprs digipeater. In telecommunications, continuous tonecoded squelch system or ctcss is a circuit that is used to reduce the annoyance of listening to other users on a shared twoway radio communications channel. About gmrs frs frequencies and ctcss the resource is currently listed in in a single category.
Press the mode to change the communication mode to analog fm mode or press and hold the ams key to turn the ams function on the ams icon appears. Ctcss codes and frequencies ei7gla diary of amateur. Ctcss does not cause your conversation to be private. Since most frs radios seem to have adopted a 1 38 subchannel system we at last have a way to express what ctcss tone we all wish to utilize with a simple number. Ctcss tones should be in the range of 500 to 800 hz.
In chirp it is called tone for transmit and tsql for receive. Decoding the secrets of ctcss while most rigs can send these lowfrequency audio tones, decoding them is a handy trick, too. If a call containing a different tone or code is received, squelch will not open and you will not hear the call. The memory channel so50on in the chart above will accomplish that. Ctcss tone is set by dip switches, or remote programming via holes 1 6. Standard ctcss tone frequencies frequencies are in hertz followed by the motorola plz designation.
This option allows you to ignore unwanted calls from others on the same frequency. Where more than one group of users is on the same radio frequency. It is known by a number of different trade names such as private line pl by motorola, channel guard cg by general electric and generically as tone squelch. Microminiature in design allows for installation in very confined areas. It does this by adding a low frequency audio tone to the voice. Decoding the secrets of ctcss while most rigs can send these low frequency audio tones, decoding them is a handy trick, too. The tx icon will appear during transmitting a call tone and tone can be heard on the speaker for confirmation.
Continuous tone controlled signalling system ctcss and. Emissions on frequencies above 30 mhz are narrowband analog fm, unless otherwise noted. Only when the correct ctcss tone is present will the amateur radio repeater be. The model nc101 is the smallest ctcss encoder on the market today, through the use of thick film hybrid technology. The nc101 is completely field tunable to any of the ctcss tone frequencies 67hz254hz without changing components or using frequency determining elements. Ctcss tone frequencies are in hertz hz or twocharacter motorola codes. Sub channel tone frequency hz sub channel tone frequency hz. The acceptance time of the tone between 200 and 400ms.
The repeater once accessed, must radiate the same ctcss tone at nominal level of 10% of maximum. Note that the repeater still needs the inbound tone before it will retransmit your signal the inbound and outbound tones may be different dcs mode digital tone squelch uses digital signals instead of a tone to do the same things dcs is new and not used much around here ctcss tone frequencies hz 67. National interoperability field operations guide version 1. Continuous tone coded squelch system ctcss is a subaudible tone signaling system sometimes referred to as plmotorolas trademark term standing forprivate line.
For our local repeater on0wv, i was looking out for a possibility to decode the assigned ctcss tone sent from friends, and next to that, detect ctcss from signals sent to other repeaters in the surrounding area, on same frequency sent from foes. In the received audio path the radios audio is routed to the tone decoder input of the chip. Jun 17, 2014 i found these devices brand new on ebay. A ctcss tone is a continuous tone coded squelch system, something brought over to the hobby from pmr. To align the frequency of the tone generator, use another transceiver with ctcss decode capability for the desired pl tone frequency. Ctcss tones laughing policeman wireless society lpws. The continuous tone coded squelch system, commonly referred to as ctcss, has been in. By ken collier, ko6ux if youre an fm operator, youll encounter ctcsscontinuous tonecoded squelch systemearly in your ham career. A single 24 pin integrated circuit capable of encoding or decoding any of the 39 standard tone frequences available. The ftm400 allowed the audio of the signal to pass only if the ctcss frequency was set to the value found in the tone sql freq option ctcss in the programmer. Other radios must have the same ctcss tone or code set to hear the transmission. A ctcss tone is subaudible and is selectable from among 42 standard tone frequencies. The bus header allows remote tone frequency programming.
Ctcss stands for continuous tone coded squelch system. Nov 14, 2015 motorolas privacy codes are a form of ctcss tone codes. The continuous tone coded squelch system ctcss allows you to ignore not hear unwanted calls from other persons who are using the same frequency. Gmrs frs frequencies and ctcss resource detail the. In telecommunications, continuous tone coded squelch system or ctcss is one type of circuit that is used to reduce the annoyance of listening to other users on a shared twoway radio communications channel. Aug 15, 20 hi all, i have not had any luck using the manual for the ft221 in installing the ss64 ctcss tone board unit. Notice, the transmit and receive functions point to the same option in the radio. Hi there, im new to radio comms so i need your help with this. Enter mxcom and one of their latest innovations in ctcss technology. These repeaters would not respond to distant weak signals on their inputs and would not repeat those signals. This standard applies to continuous tonecontrolled selective signaling ctcss with tone frequencies below 300. The main category is band plans, frequency allocations, rf spectrum that is about radio frequemcy spectrum and allocations including radio band plans.
Thats why youll often hear ctcss tones referred to as subaudibleliterally below audibility. These tones are subaudible cannot be heard and are selectable via software. A transmit high pass filter is included to reduce the possibility of false decoding. Ctcss frequencies and squelch codes may differ in some radios from thirdparty manufacturers. So50 also has a 10 minute timer that must be armed before use. Continuous tonecoded squelch system ctcss is a low continuous tone transmitted on nfm narrowband frequency modulation voice transmissions that is used to squelch and manage transmissions on a given frequency.
Ctcss stands for continuous tone coded squelch system, it is the generic abbreviation and is used to minimize cochannel interference. Ft 25rft 25e advance manual setting ctcss tone frequency the tone frequency can be selected from 50 frequencies 67. Pmr frequencies channel frequency in mhz channel number frequency 1 446. To avoid confusion, check your radio against a known motorola. Press the or key to select set mode item 8 ctcss 3. Ctcss is a system whereby a not really subaudible tone is encoded into the transmit audio of a radio and a receiver on another radio on that frequency will only open up decode when it picks up that specific tone. This is also why there are 32 tones available and also why some repeaters will not retransmit the ctcss tone. Ctcss pl tones frequencies metropolitan coordination association, inc. It will also be heard if the radio has ctcss and dcs off.
Radio frequencies are in megahertz mhz unless otherwise noted. Basically what happens is a sub audible tone is superimposed on your transmission and the repeater recognises this and opens or retransmits your signal without the need of the 1750khz tone. When the transceiver options are set to scan via software, setting the channel selector to channel 16 directs the radio to scan the selected channels from 115. It will also remove it before transmitting the required audio. Ctcss dcs description you may sometimes want to hear calls only from specific persons or groups. In addition, but optionally, access may be by a tone burst of 1750hz plus or minus 25hz at a deviation of 50% or less. To do so, select the same ctcss tone as selected by the other persons in your group. Here are some tips and resources ive found to help me use them.
They may have an intermod issue specific with that site. Ctcss repeaters would respond only to signals having the ctcss tone required for that repeater. Very handy little device if you do much with two way radio or want to find out the tone and frequency a radio is transmitting without checking the programming. In this process, you program the receive frequency with its tone mode and ctcss frequency into memory.
In telecommunications, continuous tonecoded squelch system or ctcss is one type of circuit that is used to reduce the annoyance of listening to other users on a shared twoway radio communications channel. Thats the heart of the quick tone unit with some external setup and control parts. Reed code freq hz reed code freq hz reed code freq hz reed code freq hz reed code freq hz reed code freq hz reed code freq hz reed code freq hz 1 111 349. Walmart frequencies and ctcss, dcs, csq or pl tone. As the ctcss tones are sent, the lower the frequency the longer it take for the decoder to trigger an output. Although this is not documented in the manual for the ftm400, it could turn out to be an undocumented feature that would be great to have. Ctcss dcs tone decoder and frequency counter youtube. Presented to the stamford amateur radio association by jon. Emissions on frequencies above 30 mhz are narrowband analog. The table below the screen shot contains descriptions of the tone mode and cross mode column settings for each memory channel location in the screen shot. Ctcss pl tone frequencies the purpose of ctcss is to reduce cochannel interference during band openings. This is also known as private line pl by motorola, channel guard cg by general electric and generically as tone squelch.