Why aren't Modem Ports Used Instead of Gateway Devices?

[BSalita]

Why do I even need a VTA1000 or Chat-Cord type VoIP gateway device? Why can't a notebook's modem port be used to attach a POTS phone instead?

[mberlant]

In order to function as a telephone interface and not just as a modem the modem must have a voice processor on board. A good indication that your modem is a voice modem is if it came with some sort of "answering machine" software.

Even if you have a voice capable modem you still have [at least] two more challenges ahead. The first is that there are not very many drivers written to support this functionality (Asterisk has drivers for a couple of chip sets.).

The other challenge is that the modem is FXO. That means that it behaves like a telephone set and needs to connect with a telephone switch. What you need for your suggestion is an FXS interface, which behaves like a telephone switch and expects a telephone instrument to be connected to it.

So, if you want to use your laptop for VoIP I recommend that you invest in a USB headset or handset instead of a POTS telephone set.

[BSalita]

Awesome reply. All makes sense now.

I would think that this would be a desireable feature for computer manufacturers. Seems like the additional cost would be quite small. It would get my attention as a buyer.

[mberlant]

While I could imagine a laptop with a built-in ATA in the future, I don't think it's worth the added expense over what is available today.

With a softphone and a USB headset/handset you can do everything except that you must use the PC's mouse/keyboard to place and receive calls. A USB-to-RJ11 adapter will allow you to remotely control your softphone from the attached telephone.

Given that RJ11 adapters are available today for under $100, I don't see mainstream laptop makers rushing to develop an embedded ATA.