How to Check Telephony logs

You can use telephony.registry logs to debug:

Network issues (mServiceState, mNetworkType)
Call failures (mCallState, mDataConnectionState)
SIM card errors (mSimState, mEmergencyNumberList)
Signal strength issues (mSignalStrength)

C:\Adb-drivers>adb shell getprop ril.ecclist 

adb shell dumpsys telephony.registry

Search :- mEmergencyNumberList

mEmergencyNumberList={4=[EmergencyNumber:Number-112|CountryIso-in|Mnc-|ServiceCategories-111|Urns-[]|Sources-10000|Routing-0, EmergencyNumber:Number-112|CountryIso-in|Mnc-71|ServiceCategories-0|Urns-[]|Sources-1000|Routing-0, EmergencyNumber:Number-911|CountryIso-in|Mnc-71|ServiceCategories-0|Urns-[]|Sources-1000|Routing-0], 2=[EmergencyNumber:Number-112|CountryIso-in|Mnc-45|ServiceCategories-11111|Urns-[]|Sources-1001|Routing-0, EmergencyNumber:Number-112|CountryIso-in|Mnc-|ServiceCategories-111|Urns-[]|Sources-10000|Routing-0, EmergencyNumber:Number-911|CountryIso-in|Mnc-45|ServiceCategories-0|Urns-[]|Sources-1000|Routing-0]}

Search :- mServiceState 0 for SUB1 {mVoiceRegState=0(IN_SERVICE),

mServiceState={mVoiceRegState=0(IN_SERVICE), mDataRegState=0(IN_SERVICE), mChannelNumber=1301, duplexMode()=1, mCellBandwidths=[20000], mOperatorAlphaLong=IND airtel, mOperatorAlphaShort=IND airtel, isManualNetworkSelection=false(automatic), getRilVoiceRadioTechnology=14(LTE), getRilDataRadioTechnology=14(LTE), mCssIndicator=unsupported, mNetworkId=-1, mSystemId=-1, mCdmaRoamingIndicator=-1, mCdmaDefaultRoamingIndicator=-1, mIsEmergencyOnly=false, isUsingCarrierAggregation=false, mNetworkRegistrationInfos=[NetworkRegistrationInfo{ domain=PS transportType=WLAN registrationState=NOT_REG_OR_SEARCHING roamingType=NOT_ROAMING accessNetworkTechnology=UNKNOWN rejectCause=0 emergencyEnabled=false availableServices=[] cellIdentity=null voiceSpecificInfo=null dataSpecificInfo=android.telephony.DataSpecificRegistrationInfo :{ maxDataCalls = 0 isDcNrRestricted = false isNrAvailable = false isEnDcAvailable = false LteVopsSupportInfo :  mVopsSupport = 1 mEmcBearerSupport = 1 } nrState=**** rRplmn=null isUsingCarrierAggregation=false}, NetworkRegistrationInfo{ domain=CS transportType=WWAN registrationState=ROAMING roamingType=NOT_ROAMING accessNetworkTechnology=LTE rejectCause=0 emergencyEnabled=false availableServices=[VOICE,SMS,VIDEO] cellIdentity=CellIdentityLte:{ mBandwidth=10000 mMcc=404 mMnc=45 mAlphaLong=IND airtel mAlphaShort=IND airtel mAdditionalPlmns={} mCsgInfo=null} voiceSpecificInfo=VoiceSpecificRegistrationInfo { mCssSupported=false mRoamingIndicator=0 mSystemIsInPrl=0 mDefaultRoamingIndicator=0} dataSpecificInfo=null nrState=**** rRplmn=40445 isUsingCarrierAggregation=false}, NetworkRegistrationInfo{ domain=PS transportType=WWAN registrationState=ROAMING roamingType=NOT_ROAMING accessNetworkTechnology=LTE rejectCause=0 emergencyEnabled=false availableServices=[DATA] cellIdentity=CellIdentityLte:{ mBandwidth=10000 mMcc=404 mMnc=45 mAlphaLong=IND airtel mAlphaShort=IND airtel mAdditionalPlmns={} mCsgInfo=null} voiceSpecificInfo=null dataSpecificInfo=android.telephony.DataSpecificRegistrationInfo :{ maxDataCalls = 16 isDcNrRestricted = false isNrAvailable = false isEnDcAvailable = false LteVopsSupportInfo :  mVopsSupport = 2 mEmcBearerSupport = 2 } nrState=**** rRplmn=40445 isUsingCarrierAggregation=false}], mNrFrequencyRange=0, mOperatorAlphaLongRaw=IND airtel, mOperatorAlphaShortRaw=airtel, mIsIwlanPreferred=false, Ril Voice Regist state=5, Ril Data Regist state=5, VoiceRejectCause=-1, DataRejectCause=-1, IwlanRegState=1, CellularVoiceRegState=0, CellularDataRegState=1, RilCellularDataRegState=0, CellularDataRoamingType=0, CellularDataNetworkType=0}

    mVoiceActivationState= 0

 

mServiceState 1 for SUB2, ({mVoiceRegState=1(OUT_OF_SERVICE))

mServiceState={mVoiceRegState=1(OUT_OF_SERVICE), mDataRegState=1(OUT_OF_SERVICE), mChannelNumber=-1, duplexMode()=0, mCellBandwidths=[], mOperatorAlphaLong=null, mOperatorAlphaShort=null, isManualNetworkSelection=false(automatic), getRilVoiceRadioTechnology=0(Unknown), getRilDataRadioTechnology=0(Unknown), mCssIndicator=unsupported, mNetworkId=-1, mSystemId=-1, mCdmaRoamingIndicator=-1, mCdmaDefaultRoamingIndicator=-1, mIsEmergencyOnly=true, isUsingCarrierAggregation=false, mNetworkRegistrationInfos=[NetworkRegistrationInfo{ domain=PS transportType=WLAN registrationState=NOT_REG_OR_SEARCHING roamingType=NOT_ROAMING accessNetworkTechnology=UNKNOWN rejectCause=0 emergencyEnabled=false availableServices=[] cellIdentity=null voiceSpecificInfo=null dataSpecificInfo=android.telephony.DataSpecificRegistrationInfo :{ maxDataCalls = 0 isDcNrRestricted = false isNrAvailable = false isEnDcAvailable = false LteVopsSupportInfo :  mVopsSupport = 1 mEmcBearerSupport = 1 } nrState=**** rRplmn=null isUsingCarrierAggregation=false}, NetworkRegistrationInfo{ domain=CS transportType=WWAN registrationState=NOT_REG_SEARCHING roamingType=NOT_ROAMING accessNetworkTechnology=UNKNOWN rejectCause=0 emergencyEnabled=true availableServices=[EMERGENCY] cellIdentity=null voiceSpecificInfo=VoiceSpecificRegistrationInfo { mCssSupported=false mRoamingIndicator=0 mSystemIsInPrl=0 mDefaultRoamingIndicator=0} dataSpecificInfo=null nrState=**** rRplmn= isUsingCarrierAggregation=false}, NetworkRegistrationInfo{ domain=PS transportType=WWAN registrationState=NOT_REG_SEARCHING roamingType=NOT_ROAMING accessNetworkTechnology=UNKNOWN rejectCause=0 emergencyEnabled=false availableServices=[] cellIdentity=null voiceSpecificInfo=null dataSpecificInfo=android.telephony.DataSpecificRegistrationInfo :{ maxDataCalls = 16 isDcNrRestricted = false isNrAvailable = false isEnDcAvailable = false null } nrState=**** rRplmn= isUsingCarrierAggregation=false}], mNrFrequencyRange=0, mOperatorAlphaLongRaw=, mOperatorAlphaShortRaw=, mIsIwlanPreferred=true, Ril Voice Regist state=2, Ril Data Regist state=2, VoiceRejectCause=-1, DataRejectCause=-1, IwlanRegState=1, CellularVoiceRegState=1, CellularDataRegState=1, RilCellularDataRegState=0, CellularDataRoamingType=0, CellularDataNetworkType=0}