The new V75, 55 and 35 ship in RF2 mode. You cannot use RF2 mode in the presence of any older Line 6 2.4G wireless (including Relay). If you try you will likely get failures in both the old and new units. Just say no!
You must either flash older models to the newer V2.o firmware (and you must have access to a V75 receiver and do this via Line 6 Monkey) or you can shift the newer models (or any that have been flashed with V2.0) into RF 1 mode.
RF1(XD-V30/70)Takes a new XD-V75 Receiver & computer/internet to update to RF2 10-20 MIN
RF2 (XD-V35/55/75) Easy to switch to RF1
Upgrades for Relay have not been released as of this date (but will be soon)
If an XD-V75 unit is being added to a setup that already includes any devices running in RF1 mode, the XD-V75 can be used to update the older devices to run RF2 mode by using an internet-connected computer attached to the XD-V75’s USB port. See the Firmware Updating Procedure section for more information. Alternatively, the XD-V75 transmitters can be setup to operate in RF1 mode if it is necessary to use the transmitters with older Line 6 receivers.
To set the THH12 or TBP12 transmitters (including Relay G50/90) into the RF1 mode, enter Setup mode to display the current channel, then while holding down the SELECT button press and release the ON/MUTE button on the THH12 or VALUE button on the TBP12. The display will briefly show [XD-V75 RF1] or [XD-V75 RF2] to indicate whether it is operating in the old or new mode, respectively. This setting is retained when powering off, so as a reminder the display will also show this indication [RF1 or RF2] each time power is turned on. The XD-V75 receiver will display a [To] on the far right of the display to indicate while communicating with a RF1 software transmitter.
The XD-V35 system ships set to the new dual frequency RF2 mode. To use an XD-V35 version transmitter with an earlier generation XD-V30 receiver (RF1 mode), you must change the transmitter from RF2 mode to RF1 mode. The method differs slightly between the handheld and beltpack.
• Turn the transmitter off.
• Press and hold the channel SELECT button.
• While holding the SELECT button, press and hold the power ON button.
• The blue LED over channel 1 will flash three times to indicate that the transmitter is in the RF1 mode.
• To revert to the RF2 mode, repeat the above steps; the blue LED over channel 2 will flash three times when the transmitter is in this mode.
• With transmitter off, set the Channel Select slide switch to channel 6.
• Turn on the transmitter.
• Immediately slide the Channel Select switch completely left to channel 1.
• Quickly slide the Channel Select switch completely right to channel 6.
• Quickly slide the Channel Select switch completely left to channel 1.
• This process must be completed within three seconds of turning on the transmitter.
• The blue LED will flash once to indicate that the transmitter is now in the 4-frequency transmission mode. To revert to RF2 transmission mode, repeat the above steps; the blue LED will flash twice when the transmitter is in this mode.
It is IMPORTANT to note that once you shift (in either direction) the transmitters will only remember the change if you power cycle the transmitter. Just turn it off with the power switch and then back on. If you were to pop a battery before doing this then it will revert back to the last "saved" mode.