SIP 4G Phones

SIP 4G phone

As shown in the above drawing, a 4G phone can access three types of networks:

    (a) Voice network:  this voice network was built and used before 4G network was available and it is not VoLTE (Voice over LTE).  VoLTE is a voice over IP product for the LTE network. 

    (b) LTE network: is the 4G network.  It provides the 4G phone access to the Internet.  When Internet access through the LTE network is congested, the 4G phone uses the 4G data offload network.

    (c) 4G data offload network:  this is a Wi-Fi network.  The 4G phone accesses the Internet through this data offload network when the LTE network is overloaded. The Wi-Fi network takes the 4G phone directly to the Internet as shown in the diagram.  For more on 4G data offload and Wi-Fi mesh network, see Wi-Fi Mesh

SIP VoIP software

When SIP VoIP software is installed in a 4G phone, the phone becomes:
      • SIP 4G VoIP hard-phone. It contains all the dedicated hardware of a phone.
      • SIP 4G VoIP soft-phone.  It does more work than just being a phone (smartphone.)
See SIP Phone Download  to get free SIP VoIP software for 4G phones.  Install the SIP VoIP software and turn the 4G phones into SIP 4G phones.

SIP 4G phone to phone

The above picture illustrates two simple methods that can be used by SIP 4G phones to make a SIP VoIP call.  It shows the phones initiate the communication directly with each other by using one of the accessible IP networks, either IP over LTE or IP over Wi-Fi.