DAHDI delay in outgoing call, then "call cannot be completed as dialed"

[cfapress]

I’ve got an unusual issue that happens with our DAHDI trunk.

Sometimes, not all the time, outgoing calls take 20-seconds before they ring. Then we get a TelCo message saying “your call cannot be completed as dialed”.

If I repeat the exact same process several times the outgoing call will sometimes ring within 5-seconds, as expected, and other times I get that message described above.

In checking the logs and tools I see this problem happening with the same phone line, DAHDI 1-1.

I’m wondering if there’s some signaling issue between our machine and the TelCo at this location??

I have four other systems configured the same way and none have this issue. They’re located in different areas of the state.

Any thoughts on why such an intermittent issue would happen with analog lines?

dahdi_test

Opened pseudo dahdi interface, measuring accuracy…
99.997% 99.991% 99.998% 100.000% 99.998% 100.000% 99.999% 99.995%
100.000% 99.997% 99.996% 99.997% 99.998% 100.000% 100.000% ^C
— Results after 15 passes —
Best: 100.000% – Worst: 99.991% – Average: 99.997669%
Cummulative Accuracy (not per pass): 99.998

dahdi_hardware

pci:0000:07:00.0 wcaxx+ d161:800d Digium A8B

dahdi_scan

[1]
active=yes
alarms=OK
description=Wildcard A8B
name=WCTDM/0
manufacturer=Digium
devicetype=Wildcard A8B (VPMOCT032)
location=PCI Bus 07 Slot 01
basechan=1
totchans=8
irq=0
type=analog
port=1,FXO
port=2,FXO
port=3,FXO
port=4,FXO
port=5,FXO
port=6,FXO
port=7,FXO
port=8,FXO

[lgaetz (Lorne Gaetz)]

@cfapress

Sometimes, not all the time, outgoing calls take 20-seconds before they ring. Then we get a TelCo message saying “your call cannot be completed as dialed”.

This sounds like the PBX starts dialing digits before the analog line is ready to accept. Try adding a ww prefix to outbound calls over the DAHDI trunk:

[cfapress]

Hah, that brings me back to the dial-up modem days and putting delays into the dial strings of my 2400 baud modem.

I’ve added the suggested ‘w’ and performing tests now. Results will be posted back so others may benefit from this.

[cfapress]

This appears to have resolved my issue. I have not heard any complaints over the past 1-business day.

Solution:

Connectivity > Trunks > Dahdi > Dialed Number Manipulation Rules
Outbound Dial Prefix = w

Thanks to Lorne for the quick solution!