Hello,

It looks like Freeswitch and Asterisk are the two major open source applications to build a phone system.

To relieve employees of a small business, I'd like to use either to connect a Linux host to an analog line, and perform the following tasks:
1. When a call comes in, anwswer
2. Pre-play a message to provide general information
3. Ask the user to type # if they wish to talk to an employee: Ring if so, or hang up if not.

Which application and hardware would you recommend? Can I use something smaller than a PC eg. Arduino, Raspberry, plug computers, etc.?

Thank you.

There are several really old how tos on building a answering machine using an analog voice MODEM and vgetty. I don't know if it works with a USB device or how easy it would be to expand to a full IVR.

http://www.linuxtoys.org/answer/answering_machine.html

Unfortunately you would probably never find the card or a PC it would run in...

Using a FXO card might be the fastest way but maybe not the easiest.

I would also look into a VOIP hosted service.

Thank you.

Considering the number of small shops that could use one, I'm surprised there seems to be no telephone that can 1) pick up the call, 2) play a welcome message, and 3) wait for the caller to hang up, or either ring the phone.

I don't know if there ever existed a consumer analog phone that had some basic PBX functions.

There have been some small PBX packages available but IIRC they were out of the normal users ball park on price; mostly because of ma bell and the cost of connecting it with the business lines needed.

I think with the current state of things the suggestion to use a hosting service may be the best option.