Custom Products for the Analog Radio Amateur Enthusiast

COS Activity Indication:
By asserting a change of one of the GPIO on the CM119A, the Yellow LED can indicate receiver activity by following the software status of the COS. Some code is necessary to make this work and is different for HamVoIP and AllStarLink.

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

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

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.

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

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

Mini-DIN-6 Pinout:
Click here for Mini-DIN-6 Pinout:

Recommended powering requirements and transmit audio:
The board is supplied with 5 VDC from the USB connection. The audio amplifiers run from this source of power. The available transmit audio level is 4.0V peak to peak and is enough for Kenwood, Yaesu or ICOM Amateur radios, and all commercial radios (Motorola, Tait, Kenwood, etc.), feeding the modulator pin to achieve full 5kHz deviation, at the best audio quality possible. Simply turn pre-emphasis on in the ASL software and your node will sound better than most anything else on the air.

Recommended receive audio input level:
The RA-64M accepts the widest range of audio compared to any other similar radio adapter interface . The input signal is attenuated by a potentiometer (R12), giving the broadest range of acceptable levels. As little as 20 mV P-P, and as much as 20 volts P-P is acceptable. 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 potentiometer R12. We recommend sourcing the audio from the discriminator and using the deemphasis function in the ASL software. This insures the best possible audio from your node repeater to the users and network.

All RA-64M's are supplied with a Genuine C-Media CM119A, but the RA-64M board was designed to be versatile. It will accept a CM119 (without the A) and even the CM108. 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 is available from the RA-64M main page.

Email Kevin Custer for support, ordering information, order by check, and/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 August 26, 2026, W3KKC All Rights Reserved!