Change T1 from AT&T to Verizon causes calls to drop.

[1Jumbo]

Folks,

I have a customer with a very old G3V4 load 54 si. They currently have a T1 connected via TN767E V6 to AT&T and it works fine. They have decided to change to Verizon and a new T1 has been brought in on its own smart jack. When we move the connection to the Verizon T1 and modify the route pattern to dial 1, we can dial all the numbers but the calls cut off after about 5 seconds. We do have two way transmission for the brief connection.

The LEC has sent a tech out with T-Berd and all. The circuit checks out clean. Verizon has traced the dropping calls and says we are sending the disconnect from the PBX. But the same settings work on the AT&T trunk (with the route pattern modification).

I know it is an old switch but that is not going to change. The call routes out and we can connect and get 2 way xmit. Verizon thinks we have some sort of timer which drops the call (but it does not affect the same setup on AT&T).

I am supposed to test with Verizon again tonight. Any ideas?

J

 

[4merAvaya]

Check the Answer Supervision settings on the Trunk Group. Is this an ISDN-PRI circuit?

Kevin

 

[1Jumbo]

We checked that. Played around with the "timer". I suppose we could set it out further (we tried 10 sec.).

It is a vanilla T1, robbed bit.

Thanks

 

[pbxman]

check the COR assigned to the trunk group. Page 2 -
"Outgoing Trunk Disconnect Timer (minutes):"

should be blank obviously. Just for giggles, here's our cookie-cutter AT&T trunk config:


Group Number: 2 Group Type: tie CDR Reports: y
Group Name: AT&T T1 COR: 7 TN: 1 TAC: 702
Direction: two-way Outgoing Display? n Trunk Signaling Type:
Dial Access? y Busy Threshold: 99 Night Service:
Queue Length: 0 Incoming Destination:
Comm Type: voice Auth Code? n
Trunk Flash? n

TRUNK PARAMETERS
Trunk Type (in/out): wink/wink Incoming Rotary Timeout(sec): 5
Outgoing Dial Type: tone Incoming Dial Type: tone
Wink Timer(msec): 300 Disconnect Timing(msec): 500
Digit Treatment: Digits:
Sig Bit Inversion: none
Analog Loss Group: 9 Digital Loss Group: 13
Incoming Dial Tone? y

Disconnect Supervision - In? y Out? n
Answer Supervision Timeout: 0 Receive Answer Supervision? y



TRUNK FEATURES
ACA Assignment? n Measured: both
Internal Alert? n Maintenance Tests? y
Data Restriction? n
Glare Handling: none
Used for DCS? n
Suppress # Outpulsing? n
Seize When Maintenance Busy: neither-end




Incoming Tone (DTMF) ANI: no Per Call CPN Blocking Code:
Connected to CO? n Per Call CPN Unblocking Code:

Ds1 Echo Cancellation? n





ADMINISTRABLE TIMERS

Incoming Disconnect(msec): 500 Outgoing Disconnect(msec): 500
Incoming Dial Guard(msec): 70 Outgoing Dial Guard(msec): 1600
Incoming Glare Guard(msec): 1500 Outgoing Glare Guard(msec): 1500



Outgoing Seizure Response(sec): 5
Programmed Dial Pause(msec): 1500 Disconnect Signal Error(sec): 240
Flash Length(msec): 540 Incoming Incomplete Dial Alarm(sec): 255





END TO END SIGNALING
Tone(msec): 350 Pause(msec): 150

OUTPULSING INFORMATION
PPS: 10 Make(msec): 40 Break(msec): 60





ATMS THRESHOLDS
TTL Type: 105-w-rl Far End Test No:
TTL Vendor: TTL Contact:
Trunk Vendor: Trunk Contact:
Trunk Length:
MARGINAL UNACCEPTABLE
Min Max Min Max
1004 Hz Loss: -2 21 -2 21

-Dev +Dev -Dev +Dev
404 Hz Loss: 9 9 9 9
2804 Hz Loss: 9 9 9 9

Maximum C Message Noise: 55 55
Maximum C Notched Noise: 74 74
Minimum SRL-HI: 0 0
Minimum SRL-LO: 0 0
Minimum ERL: 0 0

Allow ATMS Busyout, Error Logging and Alarming? n




TRUNK GROUP
Administered Members (min/max): 1/96
GROUP MEMBER ASSIGNMENTS Total Administered Members: 96

Port Code Sfx Name Night Mode Type Ans Delay
1: 01A1501 TN464 G e&m t1-stan 20





etc, etc, etc



pbxman
Systems Administrator

Please let Tek-Tips members know their posts were helpful.

 

[1Jumbo]

Thanks, I'll give it a try tonight.

I truly appreciate the help. You did a lot of work to do this.

J

 

[pbxman]

Not really - it was just a copy/paste from my ASA screen.

Hope it helps you out though.



pbxman
Systems Administrator

Please let Tek-Tips members know their posts were helpful.

 

[kwing112000]

AT&T has some special settings that may not work with the Verizon. I do no tknow where to change them but i have seen some old PRI'S with Megacom and Megacom8. look for something like that.

 

[1Jumbo]

Problem resolved.

On the fifth site visit, the T1 started working immediately. Verizon had revisited their design and removed echo cancellation from the circuit and now it works well with the same settings as you would use for AT&T.

Thanks for your help.

J