hope someone here can help; heres t

[phoneguy422]

hope someone here can help; heres the problem- i have a customer with an IBM AS400 server that is running on twinax cable and they want the server moved therefore we need to re-cable and I quoted the job using twisted pair cable with RJ45-twinax baluns - pretty simple so far eh?When i went to order the baluns- my supplier asked me if i wanted passive or active baluns ? how do I tell which ones I need ? thanx for any help.

 

[mradmin]

Hi, we did a similar job a couple of years ago, and twinax-to-twisted pair baluns are definitely the way to go. All of the baluns I've used have been "passive" devices in that they had no external power source. The specs from many sources allow you to specify which "pair" (on the RJ-45 side) is "active" (as in used). If they really are talking about an active (i.e., powered) device, I would think you only need it to support unusually long cable runs AND that they would cost more. There should be a spec for the max. length of the twisted pair cable, and that should help you decide. The building we did the max run was 100 meters, no problems...
Good Luck, ---Will

 

[marklouie]

Hi,
Are you using twinax hubs? or daisychaining with UTP?

I have never personally heard of an "active balun" only of active and passive hubs. Being a specialty item the cost of these seems to have increased in recent years.

The important things to remember are:

- pinning must be consistant (typically pins 4&5)

- the system is polarity sensitive.

- replacing the twinax with Cat 5 and adding baluns as required will work (but this retains most of the disadvantages of twinax)

-better to install Cat 5e in a physical star and add twinax hubs.

I have used these in the past:

http://www.transition.com/products/hubs/as400/psv.htm

(they seem to be pretty good.)

If the distances are short you can make your own passive hubs using cross connect wire and a patch panel.