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Mixing Revision B and Revision C SyncPipes and Injectors

Some of the pins in the cable between the SyncInjector and the SyncPipe changed between revision B and revision C. In reality, only two pins were affected by this change, and many installations will simply work without any special cabling changes.

With that in mind, we do recommend that you make a slight cabling change in order to ensure proper long term operation of the SyncPipe and SyncInjector. The details of this change are as follows:

  • Connect pins 1,3,4,5,7 and 8 straight through. We recommend you use the standard color codes to do this.
  • Connect Pin 2 on the Revision B device to Pin 6 on the Revision C device. This will connect the serial data correctly.
  • Leave Pin 6 on the Revision B device and Pin 2 on the Revision C device unconnected.

If you are modifying one end of a CAT5 cable, we recommend that you modify the end which plugs into the Revision B device. In this case, you would crimp all of the wires normally except those wires going to pins 2 and 6. The wire which normally goes to pin 2 (Solid Orange in T568B) should be cut off (left unconnected), and the wire which normally goes to pin 6 (Solid Green in T568B) should be connected to pin 2.

If for some reason you wish to modify the Revision C end, you would cut off the wire which normally goes to pin 6 (Solid Green in T568B) and crimp pin 2 (Solid Orange in T568B) there. It should be noted that early revision B SyncPipes are more likely to reset if they are cabled in this fashion as there will be a long wire attached to pin 6 on the SyncPipe which may pick up enough stray signal to cause the pipe to reset.

As a final note, it should be noted that the daisy chain output of a Revision C SyncInjector can be connected to either Revision B and Revision C SyncInjectors without any special cabling required.

If you are interrested in the specific change which was made, the following information may prove interesting:

Pin 2 was originally used to transmit serial data from the SyncPipe to the SyncInjector. This function has now been moved to Pin 6. Pin 2 has now been re-purposed as an additional ground conductor to help cancel out interference inducted into the Sync wire (pin 1).

Pin 6 was originally used to reset the SyncPipe remotely. In later versions (B1) this functionality was removed and Pin 6 was not connected to anything in most (if not all) revision B1 pipes. This pin has never been connected on any version B SyncInjectors.

If a Revision B SyncPipe is connected to a revision C SyncInjector with a straight through cable, the following is likely to result:

  • The serial data output on the SyncPipe (pin 2) will be connected to ground. The SyncPipe has an internal 330 ohm resistor designed to protect against this fault. This will result in the SyncPipe drawing an additional 10ma of power, and the internal resistor dissipating 1/30th of a watt of power when the SyncPipe is sending a serial mark (1). As the resistor is rated for 1/8W and the duty cycle is less than 50%, we do not expect long term damage if this is accidentally connected in this manner for an extended period.
  • Pin 6 on the SyncPipe will connected to the serial data input on the SyncInjector. As both ends are inputs (or N/C in revision B1 Pipes), we do not expect this to be a problem. However, it should be noted that we recommend that Pin 6 on revision B SyncPipes be left unconnected in any case to prevent accidental reset of the SyncPipe. Serial data will not work in any case, since the serial data output on the SyncPipe is not correctly connected to the correct SyncInjector input.

If a Revision C SyncPipe is connected to a revision B SyncInjector with a straight through cable, the following is likely to result:

  • The SyncInjector serial data input (Pin 2) will be connected to ground. As this is a high-impedance input on the SyncInjector, we do not expect this to be a problem in any case. In addition, the syncpipe serial data output (pin 6) will simply be connected to a not-connected pin on the SyncInjector. Serial data will not work in any case, since the serial data output on the SyncPipe is not correctly connected to the correct SyncInjector input.

It should be noted that even though accidental (or even intentional) connection of mismatched devices will not likely result in permanent damage, we do not recommend this configuration as we cannot guarantee that over a extended period that damage will not occur.