RTS has more than one wiring standard. All the TP stuff I've seen is wired Clear-Com standard (Pin 1 common, Pin 2 Power, Pin 3 Audio/Signal).
RTS TW (2-wire) may work with Clear-Com TW systems, but only channel 2 will function. RTS TW wiring is (Pin 1 common, Pin 2 Power & Channel 1 Audio/Signal, Pin 3 Power & Channel 2 Audio/Signal)
RTS TW stuff is usually 2-channel over 3-pin XLR.
Okay, i'm being pedantic, but just to make sure we don't contribute to what is already a pretty confusing topic....
Clearcom refers to their "2 channels on 1 XLR cable" protocol as "TW". This is not the same as "2-wire" which is a generic way to refer to Full Duplex Intercom that travels on only 2 conductors [that is, 1 XLR cable]. "2-wire" is a term used to differentiate from "4-wire" which is essentially duplex intercom utilizing 2 separate line level signals, 1 running in each direction.
Single channel Clearcom [1 channel of intercom running over 1 XLR cable] is basically the Clearcom default. So typically when someone refers to a Clearcom intercom line, this is the form of intercom they are referring to. Also typically, most manufacturers who say their equipment is "Clearcom Compatible" are referring to this form of intercom.
RTS, on the other hand, is typically 2 channels of intercom over 1 XLR cable. So typically when someone refers to an RTS intercom line they are referring to this form of intercom.
There is functionally very little difference between standard 2-channel RTS and Clearcom TW signals. The primary differences are in the nominal levels used as well as the system used to generate call signals. That being said, the 2 types of intercom can often be used together with very few issues. In fact, the newest Clearcom TW beltpacks can be converted to run as RTS beltpacks with a simple DIP switch change.
As a result, what Mac says is correct for connecting a "Clearcom" device with an RTS device. The "Clearcom" signal will appear on Channel 2 of the RTS device. This is also true when connecting "Clearcom" devices with "Clearcom TW" devices.
And yeah, i'm totally leaving out Telex Balanced Comms among other things. And we haven't even thought about Digital, and Matrix, and Intercom over IP...
Comms are fun!
[For those who know things... Please note my liberal use of the words "typically" and "primary". I'm well aware that they are Many Exceptions...]
