Xbee python 802.15.4 with api not responding

Hi,
This code seems to be working but not receiving back “hello world” ?
I can see the transmit led light-up on the grove development board. I can chat over USB with XCTU on MAC os 10.9.

#! /usr/bin/python

Import and init an XBee device

from xbee import XBee, ZigBee
import serial

ser = serial.Serial(‘/dev/tty.usbserial-AK05CKON’, 9600)

Use an XBee 802.15.4 device

xbee = XBee(ser)

To use with an XBee ZigBee device, replace with:

xbee = ZigBee(ser)

Set remote DIO pin 2 to low (mode 4)

xbee.remote_at(
dest_addr=b’\x56\x78’,
command=‘D2’,
parameter=b’\x04’)

xbee.remote_at(
dest_addr=b’\x56\x78’,
command=‘WR’)

def print_data(data):
“”"
This method is called whenever data is received
from the associated XBee device. Its first and
only argument is the data contained within the
frame.
“”"
print data

xbee = XBee(ser, callback=print_data)

xbee.tx(dest_addr=‘\x00\x01’, data=‘Hello World’)

Wait for and get the response

print(xbee.wait_read_frame())
while True:
try:
print xbee.wait_read_frame()
except KeyboardInterrupt:
break

ser.close()

I don’t see anything telling the app to do a serial.read function. I don’t even see a serial.write function either. For that matter I don’t see you calling the serial port at all.