Xeon

Original PiPhone in python is here: git clone https://github.com/climberhunt/PiPhone.git

This is very short and could probably be written in C fairly easily. It's biggest change from my other apps is the AT modem usage. Modem information is available from Adafruit along with their tutorial which has pinouts and a link to the command manual, although the original didn't get nearly that involved.

I'll probably want to figure out how to make a phone call and send an sms.

Here is some code to send SMS messages. It's written in C for RPi so it's probably a reasonable start for phone calls too. It may be necessary to disable serial port use as configured by default by the bootloader, though I kinda doubt it in my case.

To get notified when a call or message comes in I need to poll on an interrupt on a GPIO pin. The Adafruit page has a link to the reference manual that says which pins to monitor. However, the sysfs interface is now deprecated and new code is supposed to use the new character device libgpiod library Example code is available.

The UI is written and appears to work okay on both the desktop and in Xeon. I can press numbers and special characters (# and *), delete characters and exit the app. The number is displayed at the top of the display.

Next step is to port the call commands from the original app. Then wire up the modem and give it a shot. Of course, I need to order a SIM card first. Probably ought to do that soon.

The phone app will need to be rewritten now that the hardware switched to PinePhone Pro, but may be able to use some of the code/algorithms from Megi's voice calling app. There may also be some ideas that can be gleaned from dialing apps on LinuxPhoneApps.org.