It's really a simple job to get a MASS connector system wired correctly if a few basic conventions are adhered to.
"Since all MASS connectors have no gender (each connector contains both pins and sockets), what special considerations arise when designing a system and wiring these connectors?"
Because all MASS connectors are asexual with every connector containing an equal number of pins and sockets, there is only one model of chassis and inline connector for each size. However, the usual male/female type connectors are replaced with differing wiring conventions that must be adhered to in order to obtain the expected results and to ensure compatibility with existing systems.
MASS connectors are wired as either OUTPUT or INPUT connectors.
(Please refer to the diagrams below showing the wiring schemes for the W5 MicroMASS connector.)
To illustrate how this works, notice that Ch. 1 in the left side diagram (Output) is wired to pins 22, 23 and 24.
If this were attached to another connector that had been wired using the same Output pinout (with Ch. 1 on pins), there would be no way to connect Ch. 1 to Ch. 1 (pins to pins).
But if the second connector is wired as an input (right side diagram), Ch. 1 is wired to sockets 22, 23 and 24 which will mate properly with the Ch. 1 pins from the output connector.
The next connector down the line would then be wired as another output which puts Ch. 1 back on pins and it would mate with a connector that is wired as an input with Ch. 1 on sockets and so on.
The last connector in the chain will always be an input with Ch. 1 on sockets and the channels end up on the proper sets of wires within the last piece of multipair cable.
"What happens if the output to input convention isn't followed?"
If there are an unequal number of output and input connectors in a MASS system, the channels will "flip" odd to even and vice versa. That is, Ch. 1 will end up on Ch. 2 and Ch. 2 will end up on Ch. 1 --- Ch. 3 will end up on on Ch. 4 and Ch. 4 will end up on Ch. 3, etc.
If there are an equal number of inputs and outputs but they are located in the wrong places, the channels will not be flipped but this problem may surface when connecting to a different MASS system that has been wired correctly.
"Since this means that all MASS-to-MASS extension cables will have a connector wired as an input on one end and a connector wired as an output on the other end, do I have to keep track of which end is which so that I only plug the input connector into an output connector and vice-versa?"
No. If that cable gets flipped around, the signals will temporarily change which wire pairs they are traveling on inside the cable but only until they exit the other end. Then they will automatically correct themselves. That's one of the advantages of this "sexless" design. Once specified correctly, any MASS connector can be connected to any other in the world without having to worry about the usual male/female compatibility and it is not possible to mix up the channels.
"Which end of the chain do you begin with when designating outputs and inputs?"
Whirlwind's standard for wiring MASS connector systems is as follows:
The stage end of the system is considered the origination point of signals when the majority of channels are flowing from stage to console (even though some return signals can of course be flowing in the opposite direction). In this case, the first MASS connector after the stage shall be wired as an output, the next MASS as an input, the next as an output, etc. The last MASS in the chain shall be an input.
"What about return or drive snakes where all or most of the channels flow from console to stage?"
In that case, start at the other end. The first MASS connector after the signal leaves the console is wired as an output, the next an input, etc. and the last MASS is an input.
"Why does it matter from which end of the chain I start at when designating which connectors are wired as outputs and which are inputs?"
It doesn't matter for any individual system but putting the first output connector at the proper end and alternating output to input ensures compatibility with existing systems.
"MASS and MicroMASS connectors are only available in crimp (replaceable pin) style, what are the advantages of this system?"
A crimp style connector does not require soldering - the wires are attached to the pins and sockets with a crimping tool. Then the pins and sockets are inserted into the connector from the rear by pushing with the insert/extraction tool where they are engaged by spring clips that hold them in place. The other end of this tool can also be used to extract the pins or sockets should a pin become bent or the connector need to be reconfigured. When done properly, crimp connections are at least as strong and reliable as solder, maybe more so. This is the same type technology used by NASA and the military.
The solder style connectors (discontinued) have conventional solder cups on the rear of the connector and the pins and sockets are not replaceable. (Note: Solder type MASS connectors cannot be converted to crimp style.)
It is easier to assemble and reconfigure the crimp style connector over soldering in the field. The time saved can more than offset the expense of purchasing the tools necessary to achieve the crimping and insertion of the pins and sockets. If a pin is bent or broken, it can usually be removed and replaced with a new one.
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