Appreciate Fast feedbac, FXO DID issue

Unanswered Question
Mar 3rd, 2007


I have CME 4.0. I have 5 cards VIC-4 FXO. For DID we have 12 lines (No dial tone from PSTN on this tie lines) and the PSTN is using wink-start signaling.

Problem 1:

Nothing is being received on my routr for the DID ports. I did some research and found that FXO does not support wink-start. However anybody can throw an idea how can I get through this problem? Any work arround or what to use to solve this problem?

Problem 2:

INcomming calls from outside are showing as from "911". Anybody has an idea as well. I don't know if it is the due to a translation rule but if anybody can throw a solution please?

Thanks in advance,

I have this problem too.
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rhugo Sun, 03/04/2007 - 06:32

Problem 1: You are correct. FXOs don't support Wink-Start. You will have to talk to your provied to determine a different option. Not any workaround that I can think of to get this to work.

Problem 2: If it is a standard POTS line or a 1FB, you will NOT see any caller ID, check with your Telco on what your other service alternatives are.

Hope this helps...

Paolo Bevilacqua Sun, 03/04/2007 - 09:54

VIC-4FXO does not support DID, VIC2-4FXS/DID does.

To make you life easier, get ISDN BRI instead. Actually, with 10 channels, PRI is also an option.

ISDN: is digital, less ports, easy configuration, caller-ID and DID are embedded, totally standard and easy to use and diagnose. And line are never stuck.

m-haddad Sun, 03/04/2007 - 16:03

One thing I don't understand why VIC-4FXO does not support DID. Actually, my telco is sending 3 digits, for example 403. If these three digits reach the FXO port the router will know this is for extension 403? Is this right or no?

If I do change the signaling with my provider from wink-start to loop-start would my scenario work or still DID won't reach my internal extensions?

Remark: this is a temproary solution until we get our PRI installed.

Waiting for your feedback,

m-haddad Sun, 03/04/2007 - 16:16

So even if I fix the signaling problem with my Teclo this won't solve the problem?

How come this was working on their OLD PBX system?

What if I get these DIDs from the old PBX system and not from the Telco? So that the PBX will act like a translator gets the digits from the telco on the CO trunk and then passes it to an analog line connected to my FXO?

Waiting for your feedback,


m-haddad Sun, 03/04/2007 - 16:06

Since I won't see any caller-id then why I get the call from "911"?

Appreicate your feedback,


Paolo Bevilacqua Sun, 03/04/2007 - 16:37

I'm a bit confused about the caller-id you mention.

First you said that the DID lines, connected to VIC-4FXO are not working, neither incoming or outgoing calls. Is this correct, or these are partially working ?

Second, on which telephone / lines are you receiving '911' ? How is the voice port configured, and the router in general ?

If you leave the DID lines connected to the PBX, and connect the CME to PBX's extension via FXO ports, then yes, the PBX will do "conversion" and route the call to appropriate line, at this point using connection plar you should be able to route in turn to a given ephone.

m-haddad Sun, 03/04/2007 - 16:45


Sorry for missleading you. Actually, I have 12 ports from CO (Using Wink-start and they do not generated dial tone). These lines are used only for DID. What happens is that the Telco sends me the last three digits of the call.Example if somebody from outside calls 6138765431 I will receive 431 on the router and not the complete number. THese lines are not used for outbound calling. This procedure is working on their old PBX system.

I have another 8 lines where the CO generates a tone on these lines. These lines afe used for inbound and outbound calling. When I dial the pilot number 1-800-xxxxxxxx the call directly goes to the operator and shows from "911".

I hope this clarifies my scenario and really appreciate your time,


Paolo Bevilacqua Sun, 03/04/2007 - 17:15

Ok, I see now.

The DID lines, we discussed above, the best thing is get PRI, on which you can have your 800 number eventually routed too.

For the regular lines, can you send voice-port configuration, and the output of "debug vpm signal" when receiving a call?

Also, if you have a phone with caller-id handy, you can connect to one of these lines, and check what caller-id it shows, if any.

m-haddad Sun, 03/04/2007 - 17:25

Actually today is Sunday and tomorrow I shall be able to get the debug. But since you understand how is my DID working by the teclo sending only three digits, if I do set loopstart signaling with my Telco will the DID on FXO(As per my scenario) work or not?


Paolo Bevilacqua Sun, 03/04/2007 - 17:34

No it won't work. As I said before, the hardware on FXO port do not support DID lines. If you read the link that I had included above, you will understand why.

m-haddad Sun, 03/04/2007 - 18:03

Thanks I appreciate your feedback. I guess i am left with one option which is to get analog liines from the old PBX to my FXO until I get the PRI in.

Thanks Again,

pechiou Mon, 03/05/2007 - 10:56

You have another option which may or may not be acceptable to you:

1. Use 4FXS/DID analog ports. This will give you inbound DID but you lose outbound capability. So you will need the FXO ports for outbound calling. The only other "cheap" option that supports inbound DID with caller ID and DOD is the BRI interfaces.

2. You are seeing the 911 caller ID because you have have a 911 dial-peer configured and incoming calls are matching that dial-peer. I recommend that you create another dial-peer with "incoming-called ." without a destination patter configured. This dial-peer will be your "dedicated" dial-peer leg for all inbound calls to match against.

Make sense?

pechiou Mon, 03/05/2007 - 15:11

Clarification on #2, if you don't have the vic-4FXO-m, then you don't have CLID capability. You would need the VIC-4FXO-m or the VIC2.

So, given your condition, you can still configure your voice-port and assign a name to it via "station-id name" or "station-id number".

m-haddad Mon, 03/05/2007 - 15:24

I have checked the ports and they are VIC2-4FXO (Without the m) would they work?

I also checked my configuration and I didn't find any dial peer for 911 for incomming calls.

THe issue if anybody calls from outside the Call Manager express shows the calling party as "911". Would it be that the call manager express when it sees the calling party as private it shows the calling party number as 911?

Thanks and waiting for your feedback,


pechiou Mon, 03/05/2007 - 15:31

Yes, the VIC2-4FXO supports Caller ID.

Try "debug voip dialpeer" and see what callerID information is actually being delivered. I doubt it's actually 911.

m-haddad Mon, 03/05/2007 - 15:36

Well, I will debug that tomorrow and get back to you. However, if I connect these FXO ports to the PBX using analog lines from the PBX, and the PBX works as translator gets the DID call and forward it to one of the analog FXO ports on my router would that be a workable workarround until I get my PRI in? The ports from the PBX to the analog FXO lines will be like another trunk from the PBX to my router.


pechiou Mon, 03/05/2007 - 15:52

No that will not work. The reason is because the FXO port is incapable of the signaling required to transport the DID information, it's similar to E&M WinkStart. Which reminds me, E&M interfaces will work for DID _and_ DOD as well but you'd be going a step backwards, IMHO.

If there are no obstacles, the PRI would be the way to go.


Paolo Bevilacqua Mon, 03/05/2007 - 16:00

Actually, with the PBX in between CME and the DID lines, it will work.

This is because the PBX has already the DID hardware and they were using it before the CME migration. The connection between PBX and CME would be FXS/FXO and not DID.

As we discussed above, it is meant as a stopgap solution while waiting for PRI to be provisioned.

pechiou Mon, 03/05/2007 - 16:24

So the PBX can receive DID, but how does it route the calls to the CME. For the CME to ring the destination DN, it would need to know what the called-number is. How is this delivered?

Are you proposing that FXS be used and the PBX outpulse digits after the line is seized? This may work, based on the capability of the PBX. Good proposal.

With the FXO ports, when the loop closes, the ring-voltage rings the CME, what extension will the CME ring? Unless PLAR or default extension is configured, it won't know.

Paolo Bevilacqua Mon, 03/05/2007 - 16:36

Reasonably no digit can be passed and the PBX would only just allow the already existing lines to be used, just PLAR as you say, to AA-BCD or operator. I never believe that a legacy PBX can send digits out of a FXS port.

Unfortunately in this design our colleague has to put up with the cards that have been orderer as a wrong type and for sure he has to deal with the customer pressure to make things work someway.

m-haddad Mon, 03/05/2007 - 16:41


I have EVM-8FXs that requires a RJ-21 cable. If I use this to terminate the lines from the CO, I guess this would work because these FXs port support wink-start. Would you please confirm this?

Thanks for your expertise,


pechiou Mon, 03/05/2007 - 16:49

If it's the EVM-HD-8FXS/DID, then yes, you're in business. It does support DID.

m-haddad Thu, 03/08/2007 - 23:29

Hello Guys,

I guess I have survived the customer pressure as you mentioned before. Now we are using 8 DIDs on EVM-8FXS and it is working. However, I have a stupid problem which is causing the users to get mad.

Sometimes they are hearing crackling or hissing sound from incomming or outgoing calls. I did ground the router however, I am worried if there is something to be configured under the FXS ports so that crackling sound would disappear.

I appreciate any suggestion to get rid of this crackling and hissing sound.

Waiting for any feedback and again thanks for your time,


pechiou Fri, 03/09/2007 - 01:44

It could a a number of things:

1. Physical

2. hardware

3. configuration


Please review the following document and perform the recommend sweep to see which impedence setting is most appropriate. If that doesn't solve it, I'd recommend opening a TAC case ASAP; and depending on how severely it impacts the customer, consider raising priority with TAC.

m-haddad Fri, 03/09/2007 - 07:06


I will go through the document that you have sent. Could it be due a VAD issue?



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