An insight into the technology behind Vertel Walkie-Talkies

Communication devices have gone through various changes in the past few decades. Before the days of tweeting and texting, people used to communicate with the help of pagers and professional walkie-talkies. Due to evolving consumer needs, long-range Walkie – talkies have become a necessity for businesses. Management and even for households. Walkie-talkies are wireless, hand-held radio communication devices that are easy to carry anywhere. They are battery-powered transceivers and have a half-duplex channel. It means only one walkie-talkie on a channel can transmit a signal at one time. During a phone call, both the parties can interfere or add something to the conversation whereas in Walkie Talkies user needs to use a push-to-talk (PTT) button in order to speak and release the button to hear the sound coming from another unit.

There are many technologies that are used to build the best quality walkie-talkies. Let’s talk about the main technology that is CTCSS and DCS which is used for transmission.

CTCSS (Continuous Tone Coded Squelch System)

CTCSS (Continuous Tone Coded Squelch System) is an analog system used to reduce the disturbance of listening to other users on a shared two-way radio communication channel. It adds the tone to your transmission at certain frequencies. When more than one group of users is on the same radio frequency this technology mutes those users, who are using different CTCSS tone or no CTCSS. In CTCSS mode, it unmutes the signal only when it is carrying the correct sub-audible audio tone. Human ears cannot hear these tones but communication-grade speakers reduce them and filter out before sending to speakers or headphones. CTCSS tones are standardized by the EIA (Electronic Industries Alliance).


Here’s an example of how CTCSS technology is used to reduce missed messages and the distraction of unnecessary voices for other users. Suppose there are two entities communicating with each other on two-way radio frequency. Conventional radios will hear all transmissions without CTCSS going on in both groups.

DCS (Digital-Coded Squelch)

DCS (Digital-Coded System) signal spectrum occupies more bandwidth. Transmitter or receiver may not seriously distort a signal but can degrade a wide signal containing multiple frequency components during low frequency.


It is extremely important for the receiver and transmitter to be on the same frequency to achieve maximum output of DCS function. Discriminator output as a step function may pop-up because of errors in transmitter and receiver frequencies and can block the decoder for some time. In DCS operations, the occurrence of errors frequently may result in blocking out of the decoder. For reliable DCS operation, a sub-audio filter that removes low-frequency energy before audio is re-transmitted is necessary.

Why CTCSS is Different from DCS?

CTCSS (Continuous Tone Coded Squelch System) uses continuous tones below 300 Hz whereas DCS (Digital-Coded System) uses digital data or encoded-words which are very unique and all encoded words can be used on the same channel without interference. Transmitter un-keys the code at the end of transmission and just 0.5 seconds before the transmission which indicates the radio at 134 Hz tone which serves as turn off code. The FM deviation level should be in the range of 500 Hz to 800 Hz in DCS technology.

About Vertel

Vertel, a leading provider of best professional Walkie-Talkies uses multiple CTCSS/DCS technology so that you hear the best at all times. It has the best handheld walkie-talkies and best range walkie-talkies. The communication devices made by the company swear to be

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