There is no cell coverage here, so need to use a dialup for backup when broadband is down. I have a New Asus RT-N66U with TomatoUSB and was trying to get it working with a USB-to-RS232 adapter to a serial modem on a landline.
I an able to use the adapter (pl2303 chip) and the modem with no problem on my regular Linux boxen, but not under TomatoUSB (or stock ASUS for that matter). I can modprobe pl2303 and /dev/ttyUSB0 is there, and it does interface to the modem, but pppd and a chat script don't get at commands to the modem. I'm using the same chat script known to work on my other Linux box. Lsmod shows everything needed is there and the log shows nothing is being returned from the modem in response to the AT commands.