RL-20 Radio Adapter Interface Board - by Masters Communications

Custom Products from Masters Communications

Model RL-20 or RL-20M
For Two-Way Radio Applications

Pricing:

Unassembled Kit - (NO Case) $25.00 each.

Unassembled Kit with Plastic Case * - $35.00 each.

Unassembled Kit with Metal Case (Black) # - $50.00 each.

Assembled and Tested - (NO Case) $55.00 each.

Assembled and Tested with Plastic Case * - $65.00 each.

Assembled and Tested with Metal Case (Black) # - $80.00 each.

# The RL-20M comes with a black metal case.

* A 3D printed plastic 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?

The RL-20 is an AllStar Link audio interface used to make a radio-less node.
It can also be used as a simple radio adapter.
It can be used with the UA-10 adapter to replace a DMK URI.
If you're a builder, it can be done for a fraction of the cost of comparable products - Bonus!

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:
First - an explanation of what it is, and what it isn't:
The Yellow LED is a software driven indication of the status of the COS logic input. It is not required that the code be installed for the COS logic to properly function in ASL - as most radio interfaces don't even include COS activity indication. The code is only required if you want the Yellow LED to work. On the RL-20 the Gsel header selects which GPIO pin (either 4 or 8) feeds the Yellow LED (LED3) to indicate COS activity. Simply match the software to the Gsel pin chosen to drive the Yellow LED - by default - this is GPIO8. By asserting a change on one of the GPIOs on the CM119A, the Yellow LED3 position can indicate receiver activity (COS) 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.

The status of the COS can be generated by either GPIO4 or GPIO8. The Gsel 'holes' allows you to select which of these two is uesd to drive the yellow LED. This is a printed circuit trace and hole (switch) arrangement that requires cutting and soldering to change from GPIO8 to GPIO4.

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 Plastic Case)

RL-20M Unassembled Kit with Black Metal Case

RL-20 Assembled & Tested (NO Case)

RL-20 Assembled & Tested (With Plastic Case)

RL-20M Assembled & Tested with Black Metal Case

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!