4 USB TTL uarts on a USB hub - keeping them straight

[Bill Davidsen]

Robert Moskowitz wrote:
>
> On 08/22/2014 05:06 PM, Joe Zeff wrote:
>> On 08/22/2014 02:00 PM, Robert Moskowitz wrote:
>>> I found out about the lsusb command.
>>>
>>> It is reporting that they all have the same ID:
>>
>> Of course they do.  They all have the same characteristics so there's nothing
>> to tell them apart until you attach something to them.
> They are by the same company and I bought a lot of 5, so they are the same.  But
> no burnt in USB device number.  Nothing like RFID for USB devices.  Sigh.
>
> Thus I need to bring up screen and get the host to respond to figure out which
> host is which ttyusb.
>
That sounds wrong. I'm not saying I'm sure it's wrong, but I working on a system 
which was using a setup like that for status displays. They found four extra 
video screens really confusing to set up, and had some serial terminals around 
to use. From memory, they did a rule in
     /etc/udev/rules.d/70-persistent-{something}.rules
and that always gave the right names to the same devices.

I saw this in action, but I didn't set it up, I'm still looking for an easy to 
understand doc on multiple monitor setup, because I do it at most once a year 
when I get paid to relearn it. ;-)


-- 
Bill Davidsen <davidsen at tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot