Using WiModem232 with TCP/IP stack?

[qbarnes]

Now I've created a Linux droplet on DigitalOcean where I have a special login that starts the pppd daemon.  I've gotten far enough that I can get TermiteTCP to successfully initiate a PPP session and then I can start running TermiteTelnet to allow me to login to servers on the 'net via a successful DNS lookup and running Telnet over the TCP/IP connection (which is running over PPP running over telnet running over the Wimodem232  ).  However, it isn't fully working yet.  At some point the Telnet sessions always hang in various repeatable ways, and I also haven't been able to get IBrowse to load and display a page yet.  I'm currently studying the PPP logs of the bytes exchanged to find out what is happening when the sessions hang.

In the last few days, I've made more progress.  I found out the source of the hang is that for some reason the two byte sequence 0x0d 0x00 is getting turned into a single byte sequence of 0x0d.  I don't know why that is happening or what is responsible, but once I added 0x0d to PPP's escape sequence, that solved all the hangs I had been seeing.  I'm able now to pump as much data as I'd like through the PPP connection without hangs.  My PPP server is configured now with "asyncmap 200a2000 escape 0d,11,13,1d,ff".  I don't know if that's optimal yet, but it 's functional.  I'm able to load http pages in IBrowse, abet very slowly.

However, all is not happy.  The networking throughput is about at 1/3 of what it should be.  I'm seeing a lot of duplicate ACKs and packet retransmissions.  I need to track down what's causing that next.