The RE-AOL project has done some fantastic work in reverse-engineering and writing a new server backend for old AOL clients.
They are providing a TCP server, which will speak the AOL proprietary P3 protocol.
The same P3 protocol was also used over dialup and ISDN lines back in the day.
manawyrm offers AOL 3.0 compatible access to RE-AOL in the OCTOI network at 030 1234 3063.
The RE-AOL project itself is still pretty young and they seem to be missing a website. Most of their development seems to be happening in a Discord channel:
AOL access via modem¶
The AOL client software has a folder called "ccl" (communication control language?), which contains a number of scripts for different countries and access providers.
The default AOLnet provider requires the following procedure:
After the modem connect, the remote side sends: "ANSnet\r\nlogin:", to which the AOL client responds with "aol".
The remote side will then send "connected" and start speaking the P3 protocol (for example by connecting the socket over to re-aol.org).
Using ISDN via AVMs CAPI-Port driver¶
ISDN can be used to connect to AOL via X.75.
The AOL 3.0 client isn't really expecting that and needs a few special tricks.
In the client itself, under the Modem settings, configure the Setup modem string as:
ATS31=0; S36=0; S38=0; S42=0; S45=2048; S51=0^M
(which sets X.75 without compression, refer to AVMs CAPIPort manual)
As AOL 3.0 is pretty old and uses the old UNIMODEM API (which can only address low-digit COM ports), you'll need to have CAPIPort exposed as one of COM1-4. You can do this in the CAPIPort setup assistant (you might need to reinstall CAPIPort to do this, remember to reboot after uninstallation and reinstallation):
If COM1-4 are already allocated by physical/other devices, you can use Device manager to change the COM ports of those devices to higher ones.
As a final roadblock, AVM CAPIPort only sends a "CONNECT" message after it successfully connected, not "CONNECT 57600" (or similar) with a baudrate.
The connection script in the AOL client requires there to be a baudrate after the CONNECT string, otherwise it won't match and will wait forever (until timeout occurs).
You'll need to change ccl/AOLNET.CCL in AOLs installation directory as follows, to accept CONNECT without any baudrate: