Question:  I've setup a MS-704 hot mic / IFB connection to a MA-704 / PIC-4704.  When I plug in the TRS phone cable into the MA-704 the gooseneck mic on the MA-704 is disabled.  I can get MS-704 GN or HS mic audio to the MA-704 when I press the MA-704 channel buttons, is this the correct mode of operation? 
Answer:  Hot mic output from the MS-704 main station to the MA-704 control panel, when you plug in the TRS cable between the two devices the gooseneck mic input on the MA-704 is purposely disconnected so that the user has to use the gooseneck mic or headset mic on the MS-704 to talk to the IFB talent when the MA-704 control panel push buttons are activated.  The gooseneck mic / headset mic on the MS-704 main station operates normally to the PL channels A, B, C or D when the MS-704 channel talk buttons are pressed, the audio goes to the PL channels, not to the IFB talent.