UART on PIC24FJ64GB110
With your code as shown, you should have transmitted one character and then hung.

You are setting up interrupt service routines for the UART transmit and receive interrupts, but you never clear the interrupts except in the initialization.  As a minimum, you need to put:

IFS0bits.U1RXIF = 0;


inside the receive interrupt handler and

IFS0bits.U1TXIF = 0;


inside the transmit interrupt handler.

In your example, you really don't need the interrupt routines at all, you could eliminate them as long as you set IEC0bits.U1TXIE and IEC0bits.U1RXIE to 0 instead of 1.

I'm not sure whether putcUART1 waits for the transmit buffer to be empty; you may want to stick a call to BusyUART1

while(BusyUART1());


just before the putcUART1 call.