The Antenna Switch Controller PCB comes complete with all SMT components installed. All you need to add is the through-hole connectors, and headers as listed on the bill-of-material list.

You only need to add the relays that you need. If you only have two antennas, just install two relays. You can always add more in the future as your needs change.


As with any electronics construction project, take your time. Make sure you have a well lit area to work in, a fine-tip temperature controlled soldering iron, solder, a tip cleaning pad, and solder wick. A circuit board vise is handy to hold the board in place while you build it. I use this one because it’s inexpensive and does a good job. Feel free to buy one that fits your needs.

Purchase the components you need from the bill of material list before hand so you can build the board in one evening. The relay and ribbon connector pins are small on closely packed so make sure there are no solder bridges between them. If you do create a bridge use soldering wick to remove it. Also, be careful not to overheat the 10-pin ribbon connectors. It’s easy to melt the pins out of alignment.

Speaking of the 10-pin ribbon connectors. They are marked so you know where pin 1 is located. Make sure this matches up with the #1 pad on the board. The #1 pad is square where the others are round. The connector has a small triangle marking the #1 pin as shown in this photo.

Pin 1 location on the ribbon connector

I find it’s easier to install the relays first then add the connectors.


The ASC board connects to the HMI board using a 10-conductor ribbon cable. The length of this cable varies depending on where the ASC is located in the stack and whether you’re also using the Radio Antenna Switch Controller (RASC) board too. If you are, the ribbon cable will have one additional connector on it since the ASC and RASC share the Antenna Switch Control connector on the HMI board. Be sure to allow extra length for the strain-relief fold-back at each connector. This post has information on building this cable.