Calling app that doesn't require sim card and can split ring tone and voice audio on two different outputs

Question

I have a specific use case for an old Android phone (Samsung GT-I8190N) running Android 4.1.2.

The time of old land line phones are long gone, but I occasionally find it useful to be able to call "the house" at times when the kids and wife have all left their phones somewhere where they can't hear them.

My plan was to utilise this old smartphone that I will attach to the wall, and a cheap "retro" phone handset with 3.5" minijack that plugged into the headphone port. What I can't find though is an calling/messaging app that:

1. works without SIM card, and is not confusing or full of advertising, so that even small children can use it - preferably open source, but should at least have a simple screen where the user can select which person to "call" (over the Internet obviously, as there is no SIM card).

2. supports directing the ringing tone to the speaker, while the voice audio goes through the phone handset

I'm OK with installing a server application on a Linux server to route all the calls go though, and would actually prefer that, but I'm also OK with going through a 3rd party server.

Does anyone have any tips about what Android app would fit this purpose?

Answer 1

After testing numerous apps I ended up using an app called JusTalk. It doesn't tick the open source box, but it does work as intended. The ring tone comes out of the phone speaker and the conversation happens on whatever is connected to the headset connector.

Answer 2

Have you considered using Google Voice? While it doesn't necessarily meet the exact specifications you listed above, it may solve the problem you have. Google Voice is free, has an Android app (as well as ones for iOS, web, and a (probably-depreciated) Hangouts integration). You could set Google Voice to forward calls to the Google Voice number you choose to your family's cell phones, and sign in on any other devices for rings/notifications. (You can even choose which phones receive the forwarded call based on the person calling and time of day.) Also, hardware devices are available for Google Voice if you want them.