YES it can be done and relatively simply, by plugging the EQ1 module into the headphone jacks using a special loom and supplying power to the EQ1 comms module BUT there are some issues...   The existing comms side tone must be able to be reduced down to ZERO. Furthermore the old existing comms will be running as well as the EQ1. Not all comms have as good a quality as EQ1 J .  EQ1 cannot be held responsible for a lack of performance in this instance.  Some of the EQ1 features such as – No ‘bip-bop’ comfort tones on transmit and constant side tone on transmit will be unavailable.  Existing comms squelch (VOX) will need to be adjusted to lowest setting and also have multiple volume levels adjusted rather than just headset and radio.