T.38 and G.711 fax modes when Fax on Demand is used
When configuring incoming call routing to Virtual COM Ports (modems) in the case of using Fax-On-Demand should be careful with selecting T.38 mode if you want to send T.38 faxes back to caller. It should be understood that the behavior is different from the standard behavior when the fax program receives a fax. This may not allow to fully use the scenario like that shown in the example with Venta Fax script in some VoIP networks. Recall that this script allows you to receive or send a fax depending on user's selection.
To configure fax mode when Fax-on-Demand is used do the following:
1. Open Fax Voip T.38 Modem Control Panel.
2. Click VOIP in TreeView, then click Incoming Plan.
3. Select the rule that route incoming calls to Virtual COM Ports (modems). Click Edit.
4. In the VOIP Incoming Call Routing Rule window switch to the Fax panel.
5. Configure fax mode in the Fax Support area.
The following fax modes are possible (the behavior is considered in terms of Fax-On-Demand function that sends a fax during incoming call):
G711 Fax Mode (G711)
This mode is the same that the mode G711 Fax Mode (G711) in the case of outgoing calls.
Fax Voip T.38 Modem will start in the mode of sending G711 fax. In the case of receiving T.38 re-invite from the other side, Fax Voip T.38 Modem answers 'not supported' and continues to send a fax in audio mode, if the parties believe that this is possible. To set this mode in VOIP Incoming Call Routing rule:
1. Check G.711 audio fax option.
2. Uncheck T.38 fax option.
3. Uncheck Detect T.38 re-invite option.
G711 Fax + T38 Re-invite Detection Mode (T38R,G711)
This mode is the same that the mode G711 Fax + T38 Fax Mode (G711,T38) in the case of outgoing calls.
Fax Voip T.38 Modem will start in the mode of sending G711 fax. If T.38 re-invite is received from the caller side, Fax Voip T.38 Modem switches to T.38 and sends the fax according T.38 standard. If T.38-reinvite not received, Fax Voip T.38 Modem continues to use the audio mode (G711 fax) for sending a fax. To set this mode in VOIP Incoming Call Routing rule:
1. Check G.711 audio fax option.
2. Uncheck T.38 fax option.
3. Check Detect T.38 re-invite option.
T38 Fax + G711 Fax Mode (T38,G711)
This mode is the same that the mode T38 Fax with Re-invite + G711 Fax Mode (T38+R,G711) in the case of outgoing calls.
Fax Voip T.38 Modem will start in the mode of sending T38 fax (sends T.38 re-invite to the caller side). With the positive response from the caller side, Fax Voip T.38 Modem sends the fax as T.38. If the other party answers 'not supported', Fax Voip T.38 Modem switches to G711 fax and sends the fax as audio. To set this mode in VOIP Incoming Call Routing rule:
1. Check G.711 audio fax option.
2. Check T.38 fax option.
3. Uncheck Detect T.38 re-invite option.
6. Click <OK> button.
7. In the Fax Voip T.38 Modem Control Panel main window click <Apply> to save changes. Do not forget to restart Fax Voip T.38 Modem to operate with new settings. To do this click <STOP> button, then click <START> button.
Notes