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Model RL-20
For Two-Way Radio Applications

    Pricing:
  • Unassembled Kit - $25.00 each.
  • Unassembled Kit with Case * - $35.00 each.
  • Assembled and Tested - $55.00 each.
  • Assembled and Tested with Case * - $65.00 each.
    		•

    * A 3D printed case is available optionally for the RL-20 radio adapter - $10.00 each.

    Shipping and handling is calculated at checkout for US and International orders.
    First-Class shipping available to most locations worldwide, calculated at checkout.
    PayPal accepted - order below.


    RL-20 top photo - shown larger than actual size.
    Click to see COS and PTT LEDs reversed.

    What is it, and what does it do?

    As a radio-less node adapter, you would add (at a minimum) a microphone, and speaker. Driving a big speaker to louder volumes requires a audio amplifier capable of a few watts. There are plently of web articles showing how to make these types of nodes using similar 'sound card' products. The unit is available assembled and tested but without the DB9 connector or LEDs installed for those wanting to save space and enclose the adapter along with the other necessary items inside of a box. Just email Kevin (link below) to request assembly options.

    The RL-20 can also be used as a radio adapter in the simplest and most inexpensive form. It doesn't have the 555 timer protection circuit that is standard on our RA and DRA products to prevent a stuck PTT. It doesn't allow for easy installation of our optional FL-10 filters. It does, however, have large quality coupling capacitors that aren't found in cheap Chinese sound FOBs. It has a genuine crystal stabilized CM119A for the best audio quality. In our opinion the CM119B based radio interface adapters are terrible. They suffer from audio level and quality issues that are many times swept under the rug. Nothing beats the audio quality and stability of a crystal controlled CM119A, and that's why we don't offer our ASL radio interface products supplied with the CM119B.

    COS Activity Indication (or radio-less PTT indication):
    By asserting a change on one of the GPIOs on the CM119A, the LED3 position can indicate receiver activity (COS) or local PTT by following the software status of the COS logic input. Some code is necessary to make this work and is different for HamVoIP and AllStarLink. Examples for both are included below.

    When used as a radio adapter, the status of the COS can be shown with an onboard Yellow LED3. When used as a radio-less interface it's common to swap the positions of LED1 and LED3, the Red and Yellow LED's. Then - local PTT is indicated by the Red LED3 and netwrok activity is indicated by the Yellow LED1. In this role, think of the Yellow LED as a "busy" light on a radio. LED3 is driven from a CM119A GPIO when commanded to do so in software.

    In HamVoIP this code is necessary to make the LED3 option work.

    In AllStarLink this code is necessary to make the LED3 option work.

    The Purple REV3 circuit board (shown above), includes convenient connections to +5 volts for powering a DTMF microphone and a audio amplifier. It also allows the PTT and COS LEDs to be installed in reverse to better indicate the adapters operation in radio-less configuration (see the explanation below).


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    RL-20 Unassembled Kit (NO Case)

    RL-20 Unassembled Kit (With Case)

    Case Color - Use down arrow to choose.

    RL-20 Assembled & Tested (NO Case)

    RL-20 Assembled & Tested (With Case)

    Case Color - Use down arrow to choose.

    Shipping amount is calculated at checkout for shipping to most locations Worldwide.


    Support Documentation - Schematic, parts list, installation and set-up instructions and all support documantation for the RL-20 is linked inside this page.

    RL-20 Construction Article.

    RL-20 Radio-Less Explanation. Defines the signals and how they are 'backwards' when a radio interface is used in a radio-less application.

    Here's a article you can reference about building a radio-less node that uses a RL-20 interface following the explanation above.

    Custom cables available from URI Cables. They can build a custom cable for the RL-20 for many radios.

    Email Kevin Custer for ordering information, ordering by check, and/or support of this exciting product.

    Product of Masters Communications, all rights reserved.
    Specifications may change without notice.
    Images are property of Kevin Custer - W3KKC
    Board layout by Kevin Custer - W3KKC
    HTML June 3, 2020, W3KKC All Rights Reserved!