In cisco' FAQ i see:
Q. Do the Cisco 1800 Fixed-Configuration routers support voice processing or protocols?
A. No. The Cisco 1800 Fixed-Configuration routers are data-only routers but can support native voice over IP (VoIP).
Q. Are Advanced Integration Modules (AIM) supported?
A. No. AIM slots are not available.
Q. Can IP Phones be plugged into the 10/100 switch ports?
A. Yes. The switch ports also support optional PoE supplying power for the IP phones in a centralized Cisco CallManager deployment scenario.
I don't understand what means "can support native voice over IP"
I am one of the architects of C1803, C1803 is a G.SHDSL box.
C1803 would also have the switch ports inbuilt in the box.
Although C1803 is mainly intended to be a databox, it would be
wastage of BOM resource if Cisco did not support Voip on it.
You can try it out yourself, by doing the configuration and plugging in
a voip phone. Depends on which IOS SW you have though.
Sorry but i don't undertand the meaning of BOM
So, what IOS support VoIP on C1803?