[c-nsp] Cisco USB to serial cable/pinouts

Gert Doering gert at greenie.muc.de
Wed Jan 13 11:57:38 EST 2016


On Wed, Jan 13, 2016 at 08:56:28AM -0500, Eric Van Tol wrote:
> I've searched and perhaps my Google-Fu is terrible, but I cannot find the pinouts for the Cisco USB console anywhere. I would like to connect an ASR920 to a serial console server that has RJ45 inputs. I've tried using a typical USB-to-Serial adapter with the serial end connected to a DB9-to-RJ45 adapter, but get no response from the console. Can someone point me in the right direction for the pinouts so I can try to make my own cable?

I would assume that the USB port is intended to be connected to a host,
and has the USB-to-serial circuitry inside (so the host sees a serial
port) and you cannot connect another USB device to the ASR920.  The
documentation on cisco.com backs this...


I find the decision to use a "Type A" USB port for this purely amazing,
given that the USB spec explicitely forbids A-to-A cables, as that's
just not how USB works (strictly host<->device and A<->B, always, if
you have a host-to-host A-to-A cable it really has circuitry inside
to make it look like a "device" to both hosts).  Whoever designed this
has been smoking interesting weed.

OTOH, Fig. 3-23 suggests that there is a "real" USB host port 
(the "EIA Console Port") which might be able to drive a USB-to-serial,
if it's the right now - if it can be used to connect a modem, it can
be used to connect to a console server.  But I'd assume that it only
works with a Cisco Certified USB To Serial Cable, which is made by 
the Cisco Certified Optics Department and appropriately priced.


USENET is *not* the non-clickable part of WWW!
Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de
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