Thanks for your post.
Ive not used Telnet, or know what utilities are available on router firmwares, but i know linux systems, so i wonder if crontab or similar is available which can just automate/schdule that task? And then create a script with the command and even make a monitoring loop for the connection.
My line is dreadful currently, when i got fibre it was synced 37mb for 135 days, but after that it has been degrading, i have an engineer coming to look at it. This has all worked out pretty badly so far. The line is resyncing nearly every night (early hours of morning), but hope it can get back to what it used to be, sitting at 24mb now but upload is the same as it was from the start (8mb).
edit
Another idea is to use my linux server to remotely execute some commands, and have that in a bash script which is scheduled to run in crontab.
I wonder is there any way to tell if the connection has dropped from the CLI of the router? That would make it work for me, as i could just poll that every 15 mins, then run the script to remote into the router and run the commands to issue a reconnect.
edit2
From your post, maybe the process "Udhcpc" quits when the router drops connection? If there is a process monitor maybe you can check for me.
Edit3
I can just ping the Google DNS 8.8.8.8 every 1 minute, if the ping fails, I kill udhcpc process via bash script and re run the connection command remotely.
I guess the worst thing is that potentially it takes up to 11 minutes to reconnect if we assume it can take 10 mins for udhcpc to get an IP.