The RC2014/RCbus uses low cost connectors. Modules have one or two rows of angled header pins, while backplanes have one or two rows of straight header sockets. Some backplanes also have an angled socket to one end.
Single row header pins are available in two types.
Type A, also known as “positive”
This type is use by most modules, including official RC2014 “standard” bus modules.
Type B, also known as “reverse”
This connector has a profile matching the double row header pins.
Double row header pins are only available in one type.
This type is used for any modules requiring a partial or full second row, including RC2014 “enhanced” bus modules and 80-pin RCBus modules.
Type A or Type B?
While most single row modules use type A headers, it can be desirable to use type B headers in systems that also have double row modules.
Mixing single row type A headers with double row headers results in inconsistent positioning of the module PCBs. When mixing such modules it can be desirable to use type B headers for single row modules.
Also, if the backplane has jumpers between the module sockets, type A connectors can result in the module PCBs touching the jumper pins.
One benefit of type A headers is the PCB sits to the side on the module socket, making it much easier to lever the module out of its socket.
The recommendation, therefore, is to use type B headers in systems with double row modules or backplanes with jumpers.
