USB <-> serial cables for programming switches

acaeti

Member
Mar 7, 2006
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So I have to get a special serial cable to program a switch, and reading some mailing lists some people talk about getting a USB->serial cable that has a driver that lets you specify if you want the Serial end to be straight-through, null, cisco rollover, etc.

Has anyone here encountered such a device and have a recommendation? Having it work with Mac would also be a plus.

A little googling sadly turned up nothing of note.
 

Muse

Lifer
Jul 11, 2001
41,361
10,480
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I don't know about drivers with options such as you describe, but I've had two such cables. I got the first cheap at a computer show and brought it home and blew 1/2 a week trying to get it to work! I brought it back at the next computer show, a few weeks later. The vendor seemed like good people but they told me they had a policy I had to exchange for other merchandise and they wouldn't refund my money. So, I got a different USB --> Serial cable they carried but a couple more dollars. It looked a little better and it actually worked. Well, it worked at first, which was more than I can say for the other which never worked. I was using it to free up a PCI slot by virtue of running an external serial hardware modem. Keeping that modem working was a major PITA after a while, and I caved in and now use a PCI modem. So, the moral of the story is, some of those cables work, some don't, and some work better than others. I'd look for some serious recommendations before buying.

It's not that I don't have serial ports on my computer - there are two. They are both used already, however.
 

spidey07

No Lifer
Aug 4, 2000
65,469
5
76
I use one from keyspan. Works like a champ. Had bad luck with others though. This one allows you to map com ports and what not.

P/N = usa-19qw
 

TheSiege

Diamond Member
Jun 5, 2004
3,918
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are these serial ports you talk about the same as AUI? and why do they still use serial?
 

spidey07

No Lifer
Aug 4, 2000
65,469
5
76
All network gear uses a serial connection with a terminal for initial configuration.

It's also how you communicate to the network gear if there should be a problem and you can't "reach" the gear via an ip address.
 

bruceb

Diamond Member
Aug 20, 2004
8,874
111
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See if you can locate a unit made by IOGEAR Model #GUC232A
That is a USB to Serial DB-9 Male adapter and has gotten good
reviews .. I have one myself for the same purposes.
 

jlazzaro

Golden Member
May 6, 2004
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Originally posted by: TheSiege
and why do they still use serial?

serial / RS-232 is a standard thats been around since the 70s. it works well for what it needs to do, if it aint broke...ya know.
 

Muse

Lifer
Jul 11, 2001
41,361
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Originally posted by: jlazzaro
Originally posted by: TheSiege
and why do they still use serial?

serial / RS-232 is a standard thats been around since the 70s. it works well for what it needs to do, if it aint broke...ya know.
It seems that most of not all of these devices have proprietary drivers. There are MANY drivers out there to run these. I tried a number of them with my first such cable and none of them worked. I too wonder why they even make serial devices anymore after the advent and ascension of USB. There must be reasons.

 

spidey07

No Lifer
Aug 4, 2000
65,469
5
76
Originally posted by: Muse
Originally posted by: jlazzaro
Originally posted by: TheSiege
and why do they still use serial?

serial / RS-232 is a standard thats been around since the 70s. it works well for what it needs to do, if it aint broke...ya know.
It seems that most of not all of these devices have proprietary drivers. There are MANY drivers out there to run these. I tried a number of them with my first such cable and none of them worked. I too wonder why they even make serial devices anymore after the advent and ascension of USB. There must be reasons.

Simple is best. asycronous communication is always the easiest. I think USB is syncronous.