D-4 channel bank with FXO cards

D-4 channel bank with FXO cards

My system is asterisk 11 PBX Firmware:10.13.66-8 PBX Service Pack: Downloaded the distro and did a Fresh build yesterday as a test system.

Attempting to configure a Digium TE435BF connected to a Telco Systems D-4 Channel Bank equipped with FXS cards.

In order for the system to recognize the TE435BF I had to install the latest DUNDI software from Digium.

After reading what I could find on the internet, I used the DAHDI module and configured the card for FXO KS, D-4, AMI.

Utilizing the Bulk Extensions module 3 extensions where made in the same way that I have done for a FXS Digium card, assigning them to time slots1 & 2 & 3

A T1 DATS test set show Idol conditions on the A & B signaling bits from both the channel bank and the FreePbx system.

Going off hook on the FXS channel on the D-4 bank I do not get any dial tone nor do I see anything on the Asterisk CLI.

When calling the extension I get a 120 IPM busy.

After consulting with Digium Technical support we feel that either I have something misconfigured as the chan_dahdi_groups.conf does not have the expected information in it.

The chan_dahdi_groups.conf as set by FreePbx is

; [span_1]

Digium support believes that it should be

; [span_1]

This agrees whit what I have read in the Digium manual.

We changed chan_dahdi_groups.conf but it had no effect.

Thus I am unsure that I have configured the DAHDI module correctly and I am unsure that I created the extension correctly.

Any help or ideas greatly appreciated.

If the connection is over a T1, then explore using


(ear&mouth wink)

on that trunk.

(surely DUNDI should be DAHDI, no? )


E&M is not compatible with the channel bank for FXS operation as with E&M the A&B bits toggle together, IN FXO FXS signaling the A&B bits are signaled separately, A=0&B=1 is a loop start Idol condition for FXS and A=0 7 B=0 is Idol for E&M.

I did just try something however, i reset the DAHDI to ESF/B8ZS and used a Larscom CSU to down convert from ESF/B8ZS to D-4/AMI and that does work as expected. (Channel Bank requires D-4/AMI)

Thus i believe that there is something wrong with the D-4/AMI in Asterisk and / or FreeBbx and / or Digium.

I have no way of knowing.

Again any help greatly appreacated

DAHDI is a channel driver, and separate from Asterisk and/or FreePBX,

Do you actually have a context=phones ? Try from-internal, that is the hook into FreePBX and thence Asterisk

Thank you

I will try that, phones was the example in the manual.

If that does not do it i will go back to Diguim.

Thank you again.


Tried changing the context still no luck with D-4/AMI but at least ESF/B8ZS works thru a converter.

Tomorrow i will call Digium back.

Thank you again for your help