3GW Pro automatically associates an account (settings + usage history) to each SIM card used in the phone. When you switch the SIM, the current account displayed switches too.
Restriction: Dual-SIM phones are not supported (they may or may not work) because Android don’t support them in the first place, they usually rely on some proprietary add-on by the phone maker to allow the user to switch SIMs. The symptom is that 3GW may be unable to detect when you switch SIMs, and therefore will assign all usage to only one SIM. However since 3GW Pro version 1.25.0 a workaround allows to manually indicate to 3GW when you switch SIMs via your phone’s proprietary mechanism (see “Manual SIM card selection” in this blog for details).
A SIM card must be present on the first run after install, with the following exceptions:
– CDMA phones have no SIM card, but 3GW creates an account for them, associated to a fixed pseudo-SIM card number.
– [since 1.9.0] Likewise, devices without mobile internet capability (and no SIM card), such as WiFi-only tablets can be used (after confirmation). 3GW will use a fixed pseudo-SIM card to create an account.
3G Watchdog memorizes the last SIM used, so after the install if your card is missing, 3GW will show you the numbers for the account associated to this SIM.