StarTech.com 4 Port USB to Serial RS232 Adapter - DB9M - RS232 Extension - Serial to USB, TAA (ICUSB2324)

Works fine on Linux. Sees 8 ttys; /dev/ttyUSB0 - 7 Connected to stack of Cisco switches/routers all working fine at 115200 baud. No external power needed.

This item works exactly as described and is very reliable. It come with good instructions. I would purchase it again.

Needed this for old amateur radio serial connections to a newer windows 10 pc - works great. Arrived as promised. Simple and efficient.

It arrived on a weekend like 2 days after I ordered it, which is a plus. Otherwise, it works perfect for people doing console connections to networking gear, such as a Cisco lab. On the Pi, you just plug it in and away it goes, and creates /dev/ttyUSB0-7 for you, which you can open with minicom, or something like ser2net to forward TCP ports to it. I only tested with 4 of the 8 cables connected, and at 9600 N81, but it works fine without any 5VDC adapter so far. The device enumerates as 8 different entries of: Future Technology Devices International, Ltd FT232 Serial (UART) IC The only thing I found odd was that it has support for a 5V DC plug, but doesn't ship with one. Strange, but the fact that it runs off a Pi makes up for it, IMHO.

My new PC motherboard (Asus Rampage IV Extreme) no longer has any serial port. However, there are still a few things in the house that require the occasional use of a serial connection. I primarily use it to connect to a Simply Automated UPB PIM (Universal Power-line Bus Plug-in Interface Module) and run the Upstart software to configure the home UPB network. I also use it to program a URC Remote Control. I guess I could have gotten away with a dual port adapter, but the price difference is not that much. My PC runs Windows 7 64-bit. On this OS, I didn't need to install any driver myself. As soon as I plugged in the unit to my PC, Windows automatically searched the Internet, downloaded, and installed the required FTDI driver. Device Management shows the 4 new serial ports. On my machines, they are assigned Ports #6, 7, 8, and 9. They correspond one-to-one to the physical ports on the unit. Unplugging and replugging the unit didn't change the sequence, so this unit must have COM retention capability. All-in-all, I am quite pleased with it.

Works great, we have this for an automation station to work on routers via console port.