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Can not receive fax transmission over an E1 link.

We have a 3640 router connected to a PBX using an E1 connection with the following configuration:

controller E1 3/0

framing NO-CRC4

clock source internal

line-termination 75-ohm

ds0-group 0 timeslots 1-12 type e&m-immediate-start

voice-port 3/0:0


define Tx-bits idle 1001

define Tx-bits seize 0001

define Rx-bits idle 1001

define Rx-bits seize 0001

playout-delay mode adaptive

cptone PE

However when the router reload or reset due blakouts the E1 link does not UP.

What the user do to overcome the problem is erase the voice-port and E1 configuration and re-write the commands again.

The solution we have found is to change the E1 configuration to:

ds0-group 0 timeslots 1-12 type e&m-melcas-immed

However the user can not receive fax transmission now.

If the user return to the old configuration they can receive fax transmissions but the problems with the E1 interface persist.

Can someone give us a solution so the user can receive fax transmission keeping the E1 as: ds0-group 0 timeslots 1-12 type e&m-melcas-immed.

My email is:


Re: Can not receive fax transmission over an E1 link.

Often times complex troubleshooting issues are best addressed in an interactive session with one of our trained technical assistance engineers. While other forum users may be able to help, it’s often difficult to do so for this type of issue.

To utilize the resources at our Technical Assistance Center, please visit and to open a case with one of our TAC engineers, visit

If anyone else in the forum has some advice, please reply to this thread.

Thank you for posting.