Summary:ASTERISK-14894: [patch] Support for physical tapping in PRI lines
Reporter:Moises Silva (moy)Labels:patch
Date Opened:2009-09-26 20:27:23Date Closed:
Versions:Frequency of
Environment:Attachments:( 0) dahdi-tap-trunk.patch
Description:It is possible to tap E1/T1 links physically and receive 2 E1/T1 cables to receive Tx and Rx media and signaling in another box for the tapped line. This patch and Asterisk branch allows to handle this tapping lines. Asterisk (through chan_dahdi.so) will detect a call in any direction (to or from CPE/NET) and create a new call in the monitoring PBX, of course any transmission is disabled (therefore dahdi_write drop any frames being sent). Given that tx and rx are separated in 2 dahdi chans, chan_dahdi creates internally a dahdi conference that is used to mix the tx and rx streams into a single stream that dahdi_read will use to return frames to the core.

****** STEPS TO REPRODUCE ******

The DAHDI tap feature is in this branch:


The tapping feature requires libpri support from this branch:


Comments:By: Moises Silva (moy) 2009-10-05 12:03:15

I have a guy in Brazil doing heavy testing, I just asked him to report feedback here, he will do soon.

By: John Todd (jtodd) 2010-05-18 13:58:19

This is a nice feature - any feedback?

By: Evandro César Arruda (ecarruda) 2010-05-20 11:22:17

Hey Guis,

I tested and i'm using the line tapping resource developed by moy. I talked many times with Moy, when moy started to develop this i'm starting to develop to, but Moy is a very fast Guy and know much better the dahdi structure, well, perfect patch, working very very fine.

Everthing work perfect using any pri isdn variants.

Hey Mr. Tood, that feature is underful thing to put on trunk of asterisk.

If you need something, please tell to me, i can send everthing logs or reports if you need.

Thanks, thanks moy.

By: Evandro César Arruda (ecarruda) 2010-05-20 11:25:56

I tested the tapping patch with record, dial to another number ( like a chanspy ), to collect call information, and everthing worked fine on both sides.

By: Moises Silva (moy) 2010-05-20 12:33:04

there is more people using this but I lost contact of some of them.

There is someone using it in several call center environments (tapping Dialogic predictive dialer I think), he will be reporting feedback soon ( I hope he does not forget ).

By: John Todd (jtodd) 2010-05-20 18:05:42

Moy: This is really interesting stuff!  I have a few comments that you might want to consider before this gets added:  There is no documentation of any type here.  I'd suggest creating some, since I expect that will be one of the requests when this hits the reviewboard.  You might even want to create a "tapping.txt" file which describes hardware, cabling, and settings that one might use in an example configuration.  Otherwise, this is pretty obscure code to read and it may go un-noticed.

By: Ed Lacap (dishexpress01) 2010-05-22 16:48:44

Moy remotely set me up with 3 asterisk PRI T1 servers. I have 3 call centers with Dialogic card driven predictive dialers, (the old dialer software did not have digital recording enabled/licensed) & this tapping solution works great. Been using in production since December with no issues. We dial over 70,000 leads aday & each call is there.

By: Moises Silva (moy) 2010-05-22 23:12:42

jtodd: I totally agree with you, I'll put up a document in the following days.

By: antonio (antonio) 2011-01-01 07:28:11.000-0600

@moy: can you put up a document, this looks like a really nice feature