# D-Modem
Software modem with **sound**  
For burble's retro voip modem https://burble.dn42/retro/modem/  
Fortunately this old proprietary software modem still works :)

## Prerequisite
- A desktop GNU/Linux distribution, livecd is also OK
- See the original README
- Modem without any sound isn't a real modem? No problem, pulseaudio is used to output modem sound in realtime. You must have pulseaudio dev package installed on your system to compile this software.

## Step-by-step instruction

Execute these commands as a normal user:  

```
make
./slmodemd/slmodemd -e ./d-modem
screen /tmp/ttySL0 115200
```

Inside the serial console, use the following at commands:  

```
>atx3
OK
>at+ms=22,0,1200,1200
OK
>atd424026019@voip.burble.dn42
...
```

Now you should be connected. See https://burble.dn42/retro/modem/ for login username and password. Once logged in, close out of screen and execute pppd like this:  

```
sudo pppd $(readlink /tmp/ttySL0) 1200 user dn42 noauth nodefaultroute nodetach
```

nodefaultroute is used here to keep your voip alive :)  

## netns
If you would like a full dialup dn42 experience, try using netns:  

```
sudo ip netns add modem
sudo ip netns exec modem pppd $(readlink /tmp/ttySL0) 1200 user dn42 noauth nodefaultroute nodetatch
```

Start a new terminal and  
```
sudo ip netns exec modem $SHELL
unshare -m
echo 172.23.0.53 > /tmp/resolv.conf
mount --bind /tmp/resolv.conf /etc/resolv.conf
ping burble.dn42
```

Have fun!