just had a situation where i was terminating 3845 routers to PSTN smartjacks. this drove me because i was using sheilded cables and only one PRI would come up. the others were in alarm.

so i didn't think it was the cable type. i switched to regular straight thru cat5 cables and it all worked.

whats the difference ? it makes no sense. you'd think either none would come up at all. one came up so I didn't deduce that it was an issue with the cable type.

took hours to figure this out.

9/18/2008 1:03:39 AM

Are you sure it wasn't a "reboot 3 times" and it'll work issue?

or a power/connection sequencing issue?

9/18/2008 2:56:43 PM

ground shielded cables?

user error?

[Edited on September 18, 2008 at 3:07 PM. Reason : .]

9/18/2008 3:07:15 PM

get this. fcking trippy. i needed to make a crossover cable between a PBX and a 3845. so i made a crossover cable from a t1 (pins 1-2, 4-5) . . . so I take the shield out and it works fine. so i leave the shield in and noticed that the light turned green and the T1 controller was up/up . . . and this is before i plugged the other end into the PBX. very strange.


somethings not right with shielded cat5 and Cisco gear.

9/18/2008 10:38:18 PM

What kind of T1 and do you have any distance commands configured on the interface?

If its a WIC t1 v2 those are more sensitive to line voltage, and if you have distance parameters set on the WIC interface that can effect the link status. I havent touched something like this in 4 or 5 months or so... bare with me.

9/18/2008 10:55:21 PM

i can't recall the exact command, but it was cable length long 0db .... the default is 0-110 feet. i was using a 75 foot shielded t1/ds1 cable.



honestly i think cable terminalogy is a little confusing. like a cat5 cable should be a cat5 cable . . . not a t1, etc. and a crossover ethernet cable is different from a T1 crossover cable. and its even worse explaining it to someone who thinks there's no difference.

9/18/2008 11:16:08 PM