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ComTekk Software Tone generator for 2-way radio signaling. Use sound card to generate CTCSS, DTMF, tone remote, ANI and more. Synthesizer for simulation and testing of 2-way radio systems, repeaters, remote control, ANI, Paging and more

DTMF-KIT1 board for Transceiver, board for Telephone-Line and Remote-control without a HAM Transceiver

Hidden transmitter hunting, often called fox hunting or Amateur Radio Direction Finding (_ARDF_), presents a unique challenge for radio amateurs. This resource details the _PicCon_ controller, a specialized device designed to automate the transmission of signals for such events. It integrates with a standard radio transceiver, functioning similarly to a packet radio TNC, by controlling the Push-To-Talk (PTT) line and injecting audio tones or modulated CW Morse code into the microphone input. The _PicCon_ unit is field-programmable using DTMF tones received via the radio, storing all settings in EEPROM for power-off retention. Its compact design and low power consumption (a few milliamps from a 7-35VDC source) make it suitable for remote deployment. An onboard LED indicates operational status, and a push-button allows manual start/stop of transmissions without DTMF. Typically supplied as a kit, _PicCon_ includes a PCB, components, and a comprehensive manual (available in HTML, RTF, and PDF formats). The kit provides a six-conductor interface cable, but users must supply radio and power plugs due to varied configurations. Byon, _N6BG_, developed this controller, which is available from the Byonics website.

Several HD video overlay devices are offered, including the GeoStamp HD, which overlays GPS latitude, longitude, heading, speed, altitude, date, time, and depth onto AHD, HD-TVI, and HD-CVI (720p/1080p) video sources. The VideoStamp HD allows user-defined text overlays on similar HD video inputs, while the VideoStamp Keyboard HD enables text input via a PS/2 keyboard for video overlay. For commercial applications, the PostMark HD integrates with cash registers and POS terminals to overlay transaction data onto security camera feeds. Beyond HD video solutions, the DTMF-8 DTMF Decoder provides remote control capabilities for up to eight devices or relays using touch tones from a radio or other audio source. This decoder supports four operational modes and includes password protection, storing all settings in non-volatile EEPROM memory. The product line also includes standard definition OSD, RS-232, GPS, and POS text inserters, along with various DTMF encoders and DVR solutions.

This article describes how to build a general purpose DTMF decoder with a low-price chip from MITEL

DTMF Electronics Manufacturer offers Decoding, Display, Signalling, Data Logging, Remote Monitoring and Control products and design.

For over 50 years, Communications Specialists Inc. has been a cornerstone in specialized radio frequency solutions, initially gaining prominence with their **CTCSS** and **DTMF** tone signaling products widely used in amateur radio repeaters and commercial two-way radio systems. My own experience with their tone boards in various repeater builds confirms their reliability and ease of integration, a testament to their engineering. The company's legacy in tone encoding and decoding is well-established, providing robust solutions for access control and selective calling. Beyond tone signaling, Com-Spec has diversified into niche markets, including wildlife telemetry, pet tracking collars, and specialized tracking systems for model aircraft and rocketry. Their product line features compact transmitters and receivers designed for specific tracking applications, demonstrating a commitment to precision and durability in challenging environments. While some legacy products are no longer available, Com-Spec continues to innovate, as evidenced by the new R-30M receiver, which ships within five days. This focus on specialized RF applications, from tracking Alzheimer's patients to law enforcement, highlights their unique position in the radio communications industry.

DTMF Remote Controls, DTMF tone generators and broadcasting products, remote broadcasting via cell phone, cell phone mixer and remote phone keypad

Sixty-meter repeaters typically use a 1 MHz frequency separation between input and output, while 2-meter repeaters commonly employ a **600 kHz** split and 70-centimeter repeaters use a **5 MHz** offset. This article details the fundamental technical principles of amateur voice repeaters, explaining how they extend VHF/UHF communication range by receiving on one frequency and simultaneously retransmitting on another. It covers essential components such as receivers, transmitters, filters, and antennas, often situated on elevated locations for optimal coverage. The resource delves into the critical challenge of _desensing_—where the repeater's strong transmit signal overpowers its own receiver—and the engineering solutions employed, including antenna separation and the use of high-Q cavity filters. It also explores various control and timing systems, from basic squelch activation to more sophisticated microcontroller-based boards that manage functions like voice identification, time-out timers, and fault protection. Different access methods are discussed, including open access, toneburst, CTCSS subtone, and DTMF, each offering distinct advantages for managing repeater usage and mitigating interference. Furthermore, the article examines repeater linking, both conventional RF methods and modern internet-based solutions, highlighting how linking expands coverage and promotes activity across multiple repeaters or bands. It introduces less common repeater types such as 'parrot' repeaters, which use a single frequency and digital voice recording, and linear translators, capable of relaying multiple signals and modes simultaneously across different bands, often found in amateur satellites.

SvxLink is an advanced software suite for the ham radio community, initially launched in 2003 as an EchoLink application for Linux. Now a comprehensive voice services system, the SvxLink Server functions as an advanced repeater controller and can operate on simplex and duplex channels. It acts as an intermediary between transceiver hardware and applications, offering essential system services. The modular architecture of SvxLink supports customization, with modules in C++ or TCL. Key modules include a help system, parrot mode, EchoLink connectivity, DTMF repeater, voice mail, propagation warnings, and selective calling sequences. SvxLink's development and source code are available on GitHub, promoting open-source collaboration in the ham radio community.

This page describes a project involving repurposing the Weathalert receiver for controlling a radio club's beacon system remotely. The author details the modifications made to the receiver, including changing the crystal frequency and adding a DTMF decode chip and PIC for remote control. The project aims to enable the turning off of beacons to prevent interference, with plans to control each beacon and the Packet Radio digi. The article provides insights into the technical aspects of modifying the receiver and showcases the author's experimentation with different crystals for optimal performance.

INTERCOM is a freeware application designed for remote control of KENWOOD TMD700/710/V-71 transceivers, as well as other transceivers equipped with UP, DOWN, and PTT commands. Compatible with Windows XP and higher (32 & 64-bit), INTERCOM offers multilingual support in English and French, and can be used on Linux, Ubuntu, or Android platforms via WINE 1.0 or CROSSOVER. The software enables users to send basic commands—such as selecting TX, VFO, memory channels, or power levels—either through manual inputs or over a TCP/IP link. INTERCOM is tailored for SIMPLEX setups, facilitating the interconnection of VHF/UHF repeaters with nearby repeaters. Remote commands are transmitted using DTMF codes, which are decoded by SIMPLEX and forwarded to INTERCOM via TCP/IP. This functionality makes INTERCOM an ideal tool for radio enthusiasts and operators seeking seamless remote management of supported transceivers in simplex configurations.

The project aims to create a remote control system for the VK5RSE beacons located near Millicent, South Australia. The beacons on 144.550, 432.550, and 1296.550 MHz can interfere with nearby amateur radio operations, particularly for EME work on 1296 MHz. The remote control system uses a DTMF decoder and PIC microcontroller to allow turning the beacons on and off individually or in combination. The system is housed in a diecast box and powered from 5-8V. The password-protected control allows authorized users to manage the beacon operations remotely, helping mitigate interference issues for local amateurs.