I am networking 3 BCM 50's and trying to use 4 digit dialing between the 3. Site 1 is using 2200 series, site 2 is using 2300, site 3 is using 2400. I have everything programmed to what I believe is correct. Destination digits of 22, 23, 24; routing set up, ip addresses configured. However, I am getting fast busy when I dial out using 4 digit dialing. I've opened the monitor, and all digits are being sent. Any ideas?