Multi-TT USB Hubs

ModMyPi is selling Multi-TT USB hubs. I ordered a one to test the ORxPi with it. Will it resolve the current hotplug issue?

Post your ideas and findings. :smile:

They have US and EU versions as well.

I got this from a Raspberry PI forum:

Single-TT hubs perform very badly with multiple USB1.1 devices plugged in.
Hubs have a mechanism to separate low- and full-speed devices from USB2.0 high-speed devices. This is called a transaction translator - which is responsible for performing the USB1.1-speed transactions. There are two options for implementing a hub - one with a single TT for all ports (the β€œcheap” option), and one TT per port. If multiple USB1.1 devices are plugged into a hub with a single TT, then all these devices must be talked to through this TT. The FIQ enforces a one-at-a-time rule whan talking to a device behind a TT. Exclusive access to a transaction translator means that for hubs with only 1 TT there is a limit on the number of devices that can be used at any one time, or scheduling conflicts cause lost packets. USB audio is particularly vulnerable when sharing a TT with other USB1.1 devices. The use of multi-TT hubs is strongly recommended - you can get this information from a lsusb -v | less and scrolling through to the listing for the external hub.

No more hot plug issues with Multi-TT usb hubs.
This is my ORxPi with the Multi TT USB hub attached.

EDIT: Hot plugging is not working properly (i.e. HDStar) with LAN cable attached with an active router. Will test more test cases and update this on thread.