Custom Products for the Digital Radio Amateur Enthusiast
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USB Digital Radio Adapter Interface Board
For Digital Two-Way Radio Applications

Product Support Documentation
Model RA-38



Top side of RA-38 circuit board - shown slightly enlarged.
(Click photo to show a larger image)

Schematic Image - Click to download a high quality PDF.

Overview of RA-38
1, Use with Baofeng portable radios for making a AllStar Hotspot (low-power simplex node).
2, Compatible with SignaLink USB radio and speaker cables, and Plug-&-Play jumper modules.
3, Kit comes with the surface-mount components preinstalled.

Parts List:
If you purchased our kit, refer to the parts list and make sure you have all of the components you need to build it.
Click here for Parts List.

Assembly - Construction Article:
Click here for assembly instructions and construction notes - with large photos.

"JU" Jumper Settings:
Click here for Jumper Settings and other board connection assignments.

RJ45 Pinout
Click here for RJ45 Pinout.

Installation:
This device is intended to be installed inside a radio, computer, or plastic box for protection. Refer to the schematic for the pinout of the RJ45 where all of the logic signals, power connections, and audio signals are listed.

Recommended powering requirements:
The board is supplied with 5 VDC from the USB connection.

Recommended receive audio input level:
The RA-38 accepts the widest range of audio compared to any other similar radio adapter. The input signal is attenuated by a potentiometer, giving the broadest range of acceptable levels. If your receiver audio level is adjustable or programmable, we recommend around 2.0 volts P-P. This allows very good signal-to-noise ratio and low cabling cross talk. This level results in a 50% rotational setting of the potentiometer.

1/8" audio input jack:
Unlike other RA's, the RA-38 has a 1/8" jack for receive audio. This is an input which can be driven from the speaker jack on the radio - when required. This jack is switched, and when no plug is inserted, audio is routed from pin 16 of the configuration socket to the input of the board. Inserting a plug into the socket takes priority and disconnects audio that appears at pin 16.

Optional Plastic Case:
A Plastic Case is available optionally for the RA-38. Available in several colors!

Which C-Media chipset is used?
All RA series radio adapter boards are supplied with a Genuine C-Media CM119A.

The PC board was designed to be versatile. A CM108 and CM119 is also acceptable. There are slight differences between these components, and the board can be 'programmed' to accept any of the three.

Information on the CM119A.
Click here
to download a manual for the C-Media CM119A.

Secure PayPal ordering available from the RA-38 main page.

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

Product of Masters Communications, all rights reserved.
Specifications may change without notice.
Images property of Kevin Custer - W3KKC
Board layout by Kevin Custer - W3KKC.
HTML May 19, 2023, W3KKC All Rights Reserved!