[MC74xx] Dual SIM Function

Hi
We are testing MC74xx dual sim function.

Which one is the dual SIM function type?

  1. Dual SIM Dual Standby (DSDS)
  2. Dual SIM Dual Active (DSDA)
  3. Dual SIM Single Standby (DSSS)

Thanks

Hi okqqkimo1,

To my understanding:
3. Dual SIM Single Standby (DSSS)

Thx

I disagree.
MC/EM7455 has Qualcomm X7 chipset which support DSDS but nobody knows how to use it. Seems neither sierra wireless. They even don’t include dual sim AT commands set into their manuals. Weird.

Really? See AT Command Reference Rev. 3, page 115.

now they include it, since 09 November, in previous revision there wasn’t that part.
Anyway still question how to use DSDS and not DSSS mode…

Why do you think that 74xxs support DSDS? Nobody promised it, right?
Support in chipset means nearly nothing without support in device’s hardware and firmware.

neither nobody mentioned DSSS… so we can only guess.
don’t you think strange that current AT commands for SIM selection been included into manual only after our request thru sierra technical support on 2nd November?
MC7455 not a new module.
Maybe same way they didn’t mention how to use DSDS mode.

Hi All,

I saw the MC7455 has the dual SIM Function, can someone help to answer several questions?

1: How this Dual-SIM function works?
2: If we have 2 SIM card and want to let these 2 SIMs go through the mux first (VCC, CLK, DATA, RST), output of 4 muxed signals directly feed into the module, somehow we need a control signal to switch between 2 SIMs, and this control pin somehow need to talk to the MC7455, how this goal can be achieved?

Thank you

JosiahWei

  1. See example:
at!entercnd="A710"
OK
at!custom="UIM2ENABLE",1
OK
at!uims?
!UIMS: 0
 
OK
at+cimi
2500265988XXXXX
 
OK
at+cops?
+cops: 1,0,"MegaFon MegaFon",7
 
OK
at!gstatus?
!GSTATUS:
Current Time:  225              Temperature: 32
Reset Counter: 1                Mode:        ONLINE
System mode:   LTE              PS state:    Attached
LTE band:      B3               LTE bw:      15 MHz
LTE Rx chan:   1602             LTE Tx chan: 19602
LTE CA state:  NOT ASSIGNED
EMM state:     Registered       Normal Service
RRC state:     RRC Idle
IMS reg state: No Srv
 
PCC RxM RSSI:  -68              RSRP (dBm):  -93
PCC RxD RSSI:  -70              RSRP (dBm):  -95
Tx Power:      0                TAC:         2612 (9746)
RSRQ (dB):     -6.5             Cell ID:     0DC42A02 (230959618)
SINR (dB):     19.2
 
 
OK
at!uims=1
OK
at+cimi
2500163857YYYYY
 
OK
at+cops?
+cops: 1,0,"MTS RUS MTS RUS",7
 
OK
at!gstatus?
!GSTATUS:
Current Time:  263              Temperature: 32
Reset Counter: 1                Mode:        ONLINE
System mode:   LTE              PS state:    Attached
LTE band:      B7               LTE bw:      10 MHz
LTE Rx chan:   3200             LTE Tx chan: 21200
LTE CA state:  NOT ASSIGNED
EMM state:     Registered       Normal Service
RRC state:     RRC Idle
IMS reg state: No Srv
 
PCC RxM RSSI:  -77              RSRP (dBm):  -105
PCC RxD RSSI:  -80              RSRP (dBm):  -105
Tx Power:      0                TAC:         4535 (17717)
RSRQ (dB):     -8.0             Cell ID:     00060702 (395010)
SINR (dB):      8.6
 
 
OK
  1. You don’t need internal mux to work with 2 cards on 74xx. Simply connect both cards to corresponding UIM1_* and UIM2_* module’s pins and use !UIMS command to switch subscriptions (see above).