[CentOS] USB-serial adapter for CentOS 7

Wed Jul 8 15:57:54 UTC 2020
Valeri Galtsev <galtsev at kicp.uchicago.edu>


> On Jul 8, 2020, at 10:46 AM, H <agents at meddatainc.com> wrote:
> 
> On July 8, 2020 11:39:29 AM EDT, Valeri Galtsev <galtsev at kicp.uchicago.edu> wrote:
>> 
>> 
>> On 2020-07-08 10:23, Leroy Tennison wrote:
>>> I've used one on a Linux laptop, it "just worked" but the OS wasn't
>> CentOS 7.
>>> 
>> 
>> It is not clear if you used USB from APC UPS to USB port on the machine
>> 
>> side or USB - to - "serial". USB to USB with standard USB cable will
>> work.
>> 
>> If one uses serial to USB adapter on the machine side (to create serial
>> 
>> port through USB on the machine), then one _has_to_use_ APC cable: as 
>> John Pierce just said, it is APC special cable which though has serial 
>> connectors on both sides of cable, (and uses serial protocol of 
>> communication - this is already what I am saying), it does not resemble
>> 
>> neither serial nor null-modem cables.
>> 
>> Valeri
>> 
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>>> Subject: [EXTERNAL] [CentOS] USB-serial adapter for CentOS 7
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>>> 
>>> I need to connect an older APS UPS unit to a machine running CentOS
>> 7. Unfortunately the UPS only has a serial port whereas the computer
>> does not. I am aware that there are USB-serial adapters but that the
>> hardware or the drivers might fall short of expectations.
>>> 
>>> Does anyone have positive experience with such an adapter? Or,
>> conversely, would recommend avoid a particular adapter?
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>>> Leroy Tennison
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> 
> I believe I mentioned that the UPS has the serial port, the computer thus has USB.
> 

In this case, if UPS doesn’t have USB port (which will be much simpler), then as others said:

1. use USB to serial dongle attached to computer USB port (check with standard serial communicating equipment that your computer with this dongle talks serial protocol)

2. Get APC cable; this is not standard serial cables, standard cables (neither serial nor null-modem) will not work. It probably will be something like this:

https://www.amazon.com/dp/B000067OG4?tag=duckduckgo-ffsb-20&linkCode=osi&th=1&psc=1

- but take it with a grain of salt, do your own checking.

Then you will be in business.

I used APC smart UPSes for almost a couple of decades. With cables as above connected to serial port of machine (those were CentOS Linuxes). I used apcupsd, which also can be configured as master on machine directly connected to UPS, and several other machines, behind the same UPS power wise though not connected to UPS signal wise, but talking to apcupsd on master machine.

Good luck!

Valeri