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New Member

ATA 187 and Verizon modem connectivity issue

Hi,

I have the following setup

ISDN --> 2811 ---> H323 ---> CUCM 8.5 ---> SIP --> ATA 187 ---> Verizon Modem

The problem is that when I call to the modem it fails to negotiate.

If I use an ATA 186 it works.

I have the following config in the Voice GW:

voice service voip

fax protocol t38 version 0 ls-redundancy 0 hs-redundancy 0 fallback pass-through g711ulaw

modem passthrough nse codec g711ulaw

In CUCM I configured the ATA 187 to pass-through it fails. I also tested with T.38 to see if there was any difference, the same.

I configured a SIP dial-peer to have all in SIP protocol, but still the same, I heard the modem answering but after that it just disconnect. Dial-peer are g711ulaw also only one region in 711.

My question are first of all are modem supported in ATA 187 ?

If so what will be the winning combination to make it work?

By the way Fax works OK with the ATA 187 it’s only the modem device which is not.

Thanks in advance.

4 REPLIES
New Member

Re: ATA 187 and Verizon modem connectivity issue

I am pretty sure that nse modem passthrough is not supported on the ATA187, which is primarily the reason for their demise.  all of the new VG's DO support nse modem passthrough.

New Member

Re: ATA 187 and Verizon modem connectivity issue

OK...that is correct.  This is straight from Cisco's page on the ATA:

Name Signaling Event based passthrough

Name Signaling Event (NSE)-based passthrough is simply thet transport of fax or modem communications using the G.711 codec.

The ATA 187 does not support NSE-based modem passthrough.

Also this...

Modem Standards

The ATA 187 supports the following modem standards:

V.90

V.92

V.44

K56Flex

ITU-T V.34 Annex 12

ITU-T V.34

V.32bis

V.32

V.21

V.22

V.23

Fax Services

The ATA 187 supports two modes of fax services, in which fax signals are transmitted using the G.711 codec:

Fax  pass-through mode—Receiver-side Called Station Identification (CED)  tone detection with automatic G.711A-law or G.711µ-law switching.

T.38  Fax Relay mode: The T.38 fax relay feature enables devices to use fax  machines to send files over the IP network. In general, when a fax is  received, it is converted to an image, sent to the T.38 fax device, and  converted back to an analog fax signal. T.38 fax relays configured with  voice gateways decode or demodulate the fax signals before they are  transported over IP.

So with this, I would say to change your modem passthrough to an approved protocol listed above.

New Member

ATA 187 and Verizon modem connectivity issue

Thanks for the response.

I ended up using the ATA 186

Thanks

New Member

hello,

hello,

I have encountered the same problem ata 186, thank you for telling me my error
Please find below:

ISDN -> 2811 ---> H323 ---> CUCM 8.5 ---> SIP -> ATA 187 ---> ADSL modem

following config in the Voice GW:

voice service voip

fax protocol t38 version 0 ls-redundancy 0 hs-redundancy 0 fallback pass-through g711ulaw

modem passthrough nse codec g711ulaw.

My email is: soulamane@enafor.dz

I am waiting for your answer

greetings.

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