Does a simple Internet telephone interface exist?
I think perhaps not, or not at a cost less than $200.
Google finds plenty of devices, but most have complexities I just don't want.
Let me explain and specify what I'd like.
I'd like a device, probably not much bigger than a USB memory stick, which has just three connectors. Power, RJ11 and RJ45. A POE option might also be useful which would leave the power connector unused.
RJ11 connects to a standard telephone.
RJ45 connects to the Internet, either directly to a modem or through a NAT router.
Using two of these devices, with each device at a different location, I can talk to someone, just like a telephone call, who has their device connected to a standard telephone and also to the Internet.
The device will get its IP address using DHCP and perhaps light up a green LED when it's successfully obtained an IP address.
When I make a phone call I make it to a remote IP address not a phone number.
The destination IP address has another identical device connected to the Internet and to a standard telephone.
To keep it simple, the device is configured via the telephone keypad and might reply with one beep when a command is understood and actioned or with two beeps for WTF do you mean?
I might use a key sequence like ###123#124#125#126##200* which means make an outbound TCP/IP connection to a remote device where the remote device is at
123.124.125.126 and is listening on port 200. Another green LED might light up when the TCP/IP Internet connection is successfully established between two devices.The remote destination device might be configured with a key sequence such as ##200* which means listen for an inbound connection to port 200. If the device is behind NAT then a port will also have to be forwarded in the NAT router.
Other key sequences might be provided for lesser used configurations such as static IP and lockout of further configuration until reset.
Whether the configuration is retained without power depends on cost.
No complicated http configuration interface is wanted or needed but a recessed reset button would be useful to wipe all existing configuration.
Encryption is not required. If you want encryption then make a VPN between two routers.
Another useful feature might be the ability to connect one of the devices to a phone line rather than a telephone. Then my home phone can be used anywhere in the world if my remote device can establish a TCP/IP connection to my home device.
I've been doing a lot of Googling on this and found the Tiger560B but I want a device directly online, not via a computer with all the software complexities that requires. Keep the software to 8051 complexity level if possible then I can maybe write it myself. Google found other chips which could perhaps be used together to almost complete the picture. The WIZnet W7100A is nice but the serial interface, if it's fast enough, isn't going to be directly compatible with the MC14LC5480 which might then connect to a CPC5622. Perhaps the serial interface translation, a DTMF decoder, a configuration reply beep generator, and any remaining glue logic can be put in a custom chip.
There are likely to be many things I haven't thought of. Some of which might mean it isn't feasible. One possible problem is how do you know a call is coming in? Is it feasible for the device to be able to make the connected phone ring? Something tells me that this might require a transformer which makes the device a bit bigger but perhaps not too big.