I am attempting to login from a Linux client to a set top box running Linux via a USB to serial cable. When I power on the device, I can see the init messages scroll past, and I get to the login prompt, like this:

(none) login:

but I cannot login. The cursor stops flashing as if it is receiving input, but there is no response.

My serial port setup is:

Device: /dev/ttyUSB0

Bps: 115200 8N1

Hardware Flow Control: Yes

Software Flow Control: No

Any help would be greatly appreciated!