Howto:Howto get an analog modem to work with an analog adapter: Difference between revisions
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Analog adapters IP21/IP22/IP24/IP28/IP302 | Innovaphone devices has no V.150 protocol implemented - the stable transport of modem date via IP, like in fax with T.38 is not possible. Analog adapters IP21/IP22/IP24/IP28/IP302 may able to transport analog modem data via RTP cahnnel with some special settings on innovaphone devices. | ||
==Applies To== | ==Applies To== |
Revision as of 11:23, 22 October 2009
Innovaphone devices has no V.150 protocol implemented - the stable transport of modem date via IP, like in fax with T.38 is not possible. Analog adapters IP21/IP22/IP24/IP28/IP302 may able to transport analog modem data via RTP cahnnel with some special settings on innovaphone devices.
Applies To
This information applies to
- IP21 V5, V6
- IP22 V6, V7
- IP24 V6, V7
- IP28 V6, V7
- IP302 V6, V7
More Information
Problem Details
Sending Faxes over IP networks is only possible with an T.38 implementation like innovaphone uses in all Gateways. For modems there is no protocol implemented. The only way to get a working modem connection is to setup a media channel with no restriction or compression.
System Requirements
To enable fax or modem connection over RTP media channel following requirements must be fulfilled:
- a network connection with no packet loss
- LAN is only acceptable connection for this application, WAN is usually not able to fulfil the requirement
- a network connection with low delay
- LAN connection and frame size of 20 ms is required
- the voice data must be uncompressed
- G711 codec must be used exclusive
- TDM-like synchronisation between endpoints
- enables stable connection over longer period of time(available in V7)
Configuration
Following parameters that differ from the default configuration can be changed to increase the modem functionality.
Enable passive checkbox under TELx->Signaling (don't interpret FLASH and DTMF's when connected) on your appropriate TEL Interface:
Configure uncompressed codec G711 and frame size of 20 ms under Gateway/Interfaces/TELx:
Disable the echo canceler in the appropriate routing entry. Therefore go to the routing table Gateway->Routes:
Disable Echo Canceler for routes from and to appropriate analog interface:
Please keep in mind to deactivate echo canceller on whole voip path till outbreak to another analog line.
In Firmware Version 7 it is possible to get TDM Sync from remote device via IP. Make sure all devices are synchronized to device connected to the device with a TDM sync source like ISDN network.
Known Problems
Having still problems with Modem connections - disable faststart (no faststart) on the Gateway.