Altigen AltiWare OE/ACC Version 5.0 Administration Manual page 199

Board Configuration
Remote IP Phone Connecting Through DSL or Cable Modem
Figure 7. Home Network with DSL/Cable Modem
Figure 1 shows a typical home network layout with DSL/cable modem with
an IP phone and PCs. A router that supports H.323 over NAT is required
between the DSL/Cable Modem and IP phone and PCs, if the DSL/Cable
Modem does not support H.323 over NAT. If this router provides multiple
10/100 BaseT ports for devices behind NAT, the IP phone and PCs plug
into these ports. Otherwise, a hub or switch is necessary to connect this
router, IP phone and PCs.
In the case where the DSL/Cable Modem supports H.323 over NAT, the
router and the DSL/Cable Modem can be converged into a single system.
Please refer to "Setup" on page 6-16 for detailed configuration of IP phones
and routers.
AltiWare OE System Installation & Administration Manual 6-15