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New Member

E&M to PSTN problem

Hi..

I have some problem on setting up an E&M connectivity between 2 router (both were 1760)

on site A and B all of the E&M (3 card) were connected to the PBX.

we have successfully connect from :

extension-PBX-E&M-Router----Router-E&M-PBX-extension

But some strange thing happen when i try to connect to the PSTN using E&M from remote sites. We hear something like 2 tone were generated (i suspect the first tone was from PSTN and the next one is from the PBX) and after 2-3 second the dial tone turns to bussy tone(so we can not dial to the PSTN).

One other thing is there is no such problem if we connect to the PSTN using E&M from the same site :

Extension-PBX-E&M-Router-E&M-PBX-PSTN (on each site wether it was on site A and B).

So i suspect there was no problem about the wiring connectivity and pinout on each site.

But why we get the busy tone if we try it from remote site?

Is there anyone here has experiencing the same problem with me ?

any suggest will be greatly appreciated.

Thanks

Ing Hau

9 REPLIES
New Member

Re: E&M to PSTN problem

helloo...

sorry to repeating this post again...

is there anyone here can help me ?

or perhaps i'm posting on the wrong topic ?

please suggest if i do.

Thanks

Silver

Re: E&M to PSTN problem

Hard to tell without configs etc... but most problems with E&M ports are due to the cabling or the external device's config. Have a look here for more info on troubleshooting E&M interfaces:

http://www.cisco.com/warp/public/788/signalling/analog_em_ts.html

http://www.cisco.com/warp/public/788/signalling/21.html

http://www.cisco.com/warp/public/788/signalling/e_m_overview.html

New Member

Re: E&M to PSTN problem

Hi there,

yesterday i was trying to post the config here, but

it seems the config was too big.

i'll try to post some. please tell me again if there was any specific item you would like to check

or you can mail me on "inghau at perkom.co.id"

...

voice-port 0/1

input gain 7

output attenuation 7

operation 4-wire

...

dial-peer voice 105 pots

destination-pattern +1...

port 2/1

prefix 1

...

dial-peer voice 900 voip

destination-pattern 9

session target ipv4:179.15.128.132

...

New Member

Re: E&M to PSTN problem

hello A very common problem when these trying to implement cards E&M between router and a PBX

It is that both devices you must be connected to the same ground.

_____PBX ======= Router _____

| |

| |

| |

|____________________________|

| ground

__|__

___

_

New Member

Re: E&M to PSTN problem

Hi, thanks for the suggest.

Actually we have already connected the grounding as you suggest.

But seems the problem still exist.

Thanks

New Member

Re: E&M to PSTN problem

Hi Ing. E&M's are usually a royal pain and you have to work on them in association with your PBX technician. Since you say that the calls are succesfull from one side I believe that there is no cabling problem.

But I wonder why you have use the "attenuation" command on the voice port? You have to have it working first and then try to experiment on the "attenuation" and "gain" commands. I am telling this because I had a problem on these cammand which distorded the DTMF values and, as a result, my phone calls dialing was lost due to incompatibility of the DTMF levels between PBX and router.

Finally, as a suggestion on your problem try the "debug voip ccapi inout" command on both your router and will will get an complete picture on why the call attempts from the inside fail.

I hope this helped. Best regards.

New Member

Re: E&M to PSTN problem

Hi venias, thanks for your input.

i'll try to get the debug result and i'll post it here as soon as i got it.

Thanks

Ing

New Member

Re: E&M to PSTN problem

what are the pbx types? the tone is sealing tone and you have the e and m set up wronge. the one that works is set to a class a, the other is class b advanced. are these coming from the co? are you trying to use this for voice access between sites?

i have been a voice tech 30+ years

New Member

Re: E&M to PSTN problem

Hi there, firsly i would like to thank u for your response.

Yes i want to use these to access the CO lines on the other site's PBX so, there will be no more long distance call.

I don't quite remember about the PBX type but on one site they're using Panasonic

I'll post it here again after i found it.

Thanks, best regards

Ing Hau

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