I also asked this question on AskUbuntu but there nobody comments on it
I have a konig rs232 serial to usb adapter (no FTDI chip), but when I try to connect to a cisco switch/router (via Putty, screen, minicom....), sometimes it just shows nothing (But it is connected because when i remove the USB it says disconnected, and sometimes it show garbage. But it also can just work ok, for about 5-10 seconds, after that it just freezes.
I checked the adapter on an other linux pc (slackware), and here it just works flawless. I'm running ubuntu 13.10 (3-11-0-15-generic , Lenovo laptop)
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 025: ID 0cf3:3004 Atheros Communications, Inc. Bus 001 Device 032: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port Bus 001 Device 003: ID 5986:0295 Acer, Inc Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 003 Device 002: ID 058f:6366 Alcor Micro Corp. Multi Flash Reader Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
dmesg | grep 2303
[22933.099512] pl2303 1-1.2:1.0: device disconnected [22934.926969] usb 1-1.2: New USB device found, idVendor=067b, idProduct=2303 [22934.927665] pl2303 1-1.2:1.0: pl2303 converter detected [22934.929688] usb 1-1.2: pl2303 converter now attached to ttyUSB0
I borrowed another converter from a friend (this one does have a FTDI chip), but it still doesn't work. I forgot to mention that i tried it on USB 2.0 as well as 3.0