You can use the older signals that have the RJ12 telephone plug with the newer USCB board. Simply plug the plug into the socket on the board. The latch on the RJ12 male plug will slide into the RJ45 female jack with the pins correctly aligned. If you have RJ12 plugs and a crimper, you can make your own cables that plug into the USCB. This is very handy for making cables that are the right length, rather than having a lot of cable hanging down underneath the layout. This is particularly important if you have a module layout that you transport to the various train shows.
also if you buy the BLMA signals or the Details West or Tomar legacy signals before they merged with Atlas you have to do some splicing. Atlas sells the Signal Conversion Kit and a crimping tool which converts their wires to J3 so you can plug it into the board. It is also compatible with NCE and TS5. Atlas and Details West are wired to JP2 Channel 1 and set to Common Cathode BLMA and Tomar are wired to Common Anode and they operate on JP1 Channel 2 to set these Atlas includes a bag of motherboard shunts in the starter kit all you have to do is set the wires and move some jumpers.
The older signal boards use an RJ11 or RJ12 telephone-type plug - 4-wire or 6-wire (only 4 of the 6 pins in the J1, J2, J3 female jack are used). You can make your own connector cables from 6-wire flat cable, some male plugs, and a good crimper. The new signal boards use an RJ45 ethernet-type plug - 8-wire. You can make your own connector with some ethernet cable and male plugs. You may be able to use your crimper as there usually is two slots - one for RJ11-RJ12, and another for RJ45 male plugs.
The ability to use common anode or common cathode signals is a major advancement with the Atlas 2018 USCB. In the older 2006 SCB, the return was "common cathode". The common return for all LEDs in the signal mast were the negative wires. If the LEDs in a signal mast were "common anode" - ie the return wire was the positive wire - you couldn't use these signal masts with the 2006 Atlas SCB. With either "common anode" or "common cathode" return, simply by moving a jumper plug, you can use pretty much any signal mast out there on the market - provided you know how to connect the wires to the proper pins in the RJ45 female jack, you have a spare plug, and you have a crimper to crimp on a plug.
You can wire the system with only 4 wires and remember that you have too insulate both rails at both ends of the block or you'll get feedback through the oil that you don't insulate.
