2 e1 controller cards back to back

Unanswered Question
Feb 5th, 2008

Hi all, is it possible for me to plug my 2 routers in back to back via the e1 card in it, and how to I configure all 1-32 timeslots to make use of the full 2 mega bandwidth ?

I have this problem too.
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graemeporter Tue, 02/05/2008 - 05:55

Hi Carl,

Yes, you can do it - best bet is to use an RJ-48 crossover cable. Connecting the two back-to-back like this should at least bring up the Carrier Detect light.

As for the next bit - I've only ever done this for an E1 used for voice connecting to a circuit to the PSTN, not for data at all, so excuse any mistakes I make. If anyone spots anything wrong, please let me know as I'd love to learn too!

If it's a dual-purpose E1/T1 WIC you're using, you'll need to specify what mode it should operate in. Use the "card type" command to specify E1 mode for your card (assuming it's port 0 on the E1 card in WIC slot 0):

router(config)# card type e1 0 0

Once that's done, you should be able to set the number of timeslots to use:

router(config)# controller E1 0/0/0

router(config-controller)# pri-group timeslots 1-31

router(config-controllet)# end


At this point, the router should create interfaces for all your timeslots. You will need to do this on both your routers.

You should then be able to set IP addresses on the E1 interfaces, on the signalling channel:

router(config)# interface serial 0/0/0:15

router(config-if)# ip address

router(config-if)# no shutdown

Obviously, on the other router, you would set

From here, I draw a complete blank. If you can PING across between the two 10.x.x.x IP addresses, great. If not, hopefully someone more experienced than me can help you out.

Hope this is at least a good starting point for you.

Kind regards,


carl_townshend Tue, 02/05/2008 - 06:55

Hi Graeme

Do you need to use the rj48 crossover cable here ? cant you use an rj45 ?



rgodden Tue, 02/05/2008 - 07:26

As they say on Blue Peter, here is two i made up earlier, UTP will work over a short distance as long as the pin outs are correct

carl_townshend Tue, 02/05/2008 - 23:30

what do you mean by pin outs are correct? so can I use a normal car 5 cable, say 2 meters ?

carl_townshend Mon, 02/11/2008 - 05:26

I have used a normal rj45 cable to connect the routers back to back, but im getting this, any ideas ?

E1 0 is down.

Applique type is Channelized E1 - balanced

Far End Block Errors Detected

Receiver has loss of signal.

alarm-trigger is not set

Version info Firmware: 20020306, FPGA: 11

Framing is CRC4, Line Code is HDB3, Clock Source is Line.

Data in current interval (72 seconds elapsed):

0 Line Code Violations, 0 Path Code Violations

0 Slip Secs, 72 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 72 Unavail Secs

rgodden Mon, 02/11/2008 - 05:47

what are the pin outs of the cable, what pins have you crossed to get an e1 crossover cable, do a search for e1 crossover on cisco will give you the answer

microtel Tue, 02/12/2008 - 03:46

Hi Carl,

Did you resolve your problem ..i have the same

Any informations about E1 Crossover??



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