How to receive-send a fax using the Huawei E173 modem?

Question

Huawei

The task is to send and receive faxes via the Huawei E173 modem (it also supports facsimile functions).
E173u-1 modem, everything is unlocked, voice activated, firmware 11.126.15.00.00
Testing on Vodafone (Ukraine - former MTS), and ultimately it will all work on T-Mobile (USA)
Trying to work with the modem via Asterisk on Linux + asterisk-chan-dongle - everything works (in voice mode).
When trying to send a fax via a modem from Windows using VentaFax, it says that the subscriber is not answering (although the fax does not actually ring). If you try to just call from the modem to a fax - the call goes. When trying to receive a fax via modem from Windows using VentaFax, it does not see an incoming fax call.
What did I forget/not take into account? Maybe somehow you need to set up a connection through this modem? Give a command to switch to the "only 2G networks" mode (like AT ^ SYSCFG = 13,1,3fffffff,0,0)? Something else?

Answer 1

Hello.
To do this, your cellular phone (or cellular modem) must be capable of receiving faxes. Although it may seem paradoxical, cell phones do not have command-compatible voice features with voice modems. The exceptions are some models of GSM modems released by Huawei, for example, E173. They have support for both fax and voice functions.
Not every cell phone supports fax transmission. Very often, the phone manufacturer neglects support for fax commands in favor of more fancy multimedia features. Therefore, the high price, modernity and "sophistication" of the phone does not guarantee the presence of fax support in it. We do not monitor the cellular phone market and do not study them for the support of this or that model of facsimile functions. Read the manual for your phone or contact the phone manufacturer's support service with a question, and if you are still choosing a fax-enabled phone for yourself, contact the sales assistant in the store for help.
There are phones (smartphones) running their own operating system. For some of these phones, there is special software for receiving and transmitting faxes that runs directly on the phone running this operating system. But such devices usually do not support fax communication, being connected to a personal computer as an external modem. In particular, this applies to smartphones with the Android operating system.
Some cellular operators (for example, Skylink, the operator of the CDMA450 standard in the St. Petersburg region) do not provide a fax reception service in their network. Most other operators support this service, but it must be activated by them for your account. For all questions related to the support of the fax operator's network, please contact the operator's technical support service.
Setting up the program to work with a cell phone as a modem is no different from conventional modems and is described in the Help section "First Steps". The method of connecting the phone to the computer (cable, infrared, Bluetooth) is of no fundamental importance.
www.ventafax.ru/faq.html 3/8
06.06.2019 VentaFax: Frequently Asked Questions
Peculiarities of operation of cell phones and modems are described in the Help section "GSM telephony and fax reception and transmission". This information also applies to phones of other digital standards. For more information regarding Huawei GSM Voice Modems, see "Huawei GSM Voice Modems". Note that a cellular phone or modem cannot be switched from voice to fax without disconnecting the connection. This means that you will not be able to make a call, then talk and send a fax in the same session. For Huawei voice modems, this means that it is impossible, for example, to use a voice prompt before sending a fax during automatic broadcasting.