On Wed, Feb 24, 2021 at 8:59 PM Brian K. White <[email protected]> wrote:

>  > if you want to use rj45 -> db25 hoods, you should check out a cable
> like https://www.amazon.com/gp/product/B078PT5N24
> <https://www.amazon.com/gp/product/B078PT5N24> which will just plug into
> an android device with usb c port and give you a rj45 end to plug into
>  > --francois
>
> Then you still have to cut off the rj45 end and solder on a db25.
>
> It also  assumes the android device has a usb-c jack.
> I made an equally unsafe assumption that the android device has micro-usb.
>
> If you're assuming usb-c, you could combine the OTG cable and usb-serial
> in one with this:
> https://www.amazon.com/dp/B074VM88G1
> Then you just need the serial cable I showed, or the two mini adapters
> in the mComm manual.
>
> I guess the advantage with the usb-c adapter is, if you have both a new
> phone and a new laptop, then they both have the same usb-c jacks, so the
> same adapter works on both without an extra OTG cable for the phone.
>

  You wouldn't cut off the rj45 adapter, you'd use an rj45-db25 hood either
pre-wired or one you custom -- wired
https://www.amazon.com/InstallerParts-Female-Modular-Adapter-Ivory/

Not so much these days, but it was common to have multiport serial servers
terminate in rj45 so you could either connect them directly to console
ports (with, for example, cisco devices) or wire them up to appropriate de9
and db25 adapters.  because the adapters are inexpensive, you could easily
have them terminate as straight through or null modem, and this was helpful
for servers that had very particular serial console pinouts.

the OP mentioned using these connectors already, I have boxes of them
somewhere myself so it's a way of leveraging existing hardware.  it
wouldn't be efficient to use a usb -> 9pin usb serial adapter, then a 9pin
-> rj45 cable, then an rj45 to db25 hood (but it would work!).  also, the
rj45 -> db25 wired as a null modem takes up less space behind the m100 than
a usb -> serial adapter and the matching slim null modem and de9->db25
adapter (unless you've created a custom connector).

i linked to a usb c cable, you can get a similar cable with usb a and use
it with an otg adapter.  my favorite usb serial adapter is
https://www.amazon.com/DTECH-Serial-Adapter-Supports-Windows/dp/B01AT2FTOU/
as it has both 9pin and 25 pin availableat a right angle, but you still
need a null modem adapter

However your cable is short, which is a different advantage I didn't
consider --- you don't want 6ft of cable between 2 devices that are going
to be close together!

--francois

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