How to append w to all outbound PSTN calls

I’m having an odd problem with my POTS lines. The last digit tone is being cut off from the dial strings going out of my analog card. I was able to verify this with a Harris test set alligator clipped to stripped wires. The CLI prints Called DAHDI/1/311 yet i can only hear the 3 and the 1 and then receive an error from the telco about the number dialed. My outbound route and trunk settings are standard. Does anyone have any ideas?

Rhino support told me that there is an Asterisk bug that causes the last digit to be delayed several seconds. They say to add a w to the end of the dialing string. How do i add this to all outgoing calls in freepbx? I know how to prepend but not append. TIA

Rhino Ceros 1U with 4FXO on Rhino RCB8FXX card
PBX in a Flash Version = 1.7.5.6 Running on HARDWARE
FreePBX Version = 2.8.1.4
Running Asterisk Version = 1.8.6.0
Asterisk Source Version = 1.8.6.0
Dahdi Source Version = 2.5.0.2+2.5.0.2
Libpri Source Version = 1.4.12
Operating System = CentOS release 5.7 (Final) Kernel Version = 2.6.18-238.9.1.el5 - 32 Bit

I found this bug:
https://issues.asterisk.org/jira/browse/ASTERISK-1988
The comment attributes the behaviour to echo training. I changed echotraining=800 to no and fixed it.