Firefox OS/DSDS

Introduction of DSDS

DSDS, abbreviation of Dual-SIM-Dual-Standby, means you could have both SIM cards ready to receive incoming calls and incoming messages while the two cards are in 'standby' state, e.g.. none of it is used in-call. In standby state, your friend can reach you with either SIM_1 or SIM2. However, if your friend tries to call your SIM_2 while you are in call with SIM_1, then your friend cannot reach you until the original call on SIM_1 is released. In DSDS, you can have data connections on one SIM card at a time. If you like to set up a data connection via that said SIM_1, then the connection on SIM_2 needs to be disconnected first if any.

Version 1.3

FFOS v1.3 is going to provide a basic set of DSDS user experience. UX_Spec_for_v1.3 is the latest UX specification for FFOS v1.3.

In general, in v1.3, user could choose one SIM card as a primary one for different purposes -- making an outgoing call, sending text messages and setting up data connections. That said, once user has chosen SIM_2 as the primary one for outgoing calls, a new call is always dialed out via SIM_2 unless user changes the setting.

Terminologies

• Primary SIM

The one which the user chooses to make outgoing calls (for voice) and/or the one which the user chooses to make data calls (browsing).

• Active SIM

The one on traffic channel (in call or data). For calls, It could be primary (outgoing, incoming) or non-primary (incoming). WRT data calls, Active SIM will be same as the primary SIM for data. (as there is no incoming/outgoing separation there).