Started experimenting with baresip as PSTN dialer

app/src/main/kotlin/com/tutpro/baresip/BaresipService.kt

@@ -1748,6 +1748,77 @@ class BaresipService: Service() {
         }
     }
 
+    fun handleExternalCall(telecomCall: android.telecom.Call) {
+        val uri = telecomCall.details.handle?.schemeSpecificPart ?: "Unknown"
+        Log.d(TAG, "Handling external call from $uri")
+
+        if (uas.value.isEmpty()) {
+            Log.e(TAG, "No User Agents available to handle external call")
+            return
+        }
+        val ua = UserAgent.statusMap().keys.firstOrNull()?.let { UserAgent.ofAor(it) } ?: uas.value[0]
+
+        val telecomState = if (VERSION.SDK_INT >= 31)
+            telecomCall.details.state
+        else
+            @Suppress("DEPRECATION") telecomCall.state
+        val initialStatus = when (telecomState) {
+            android.telecom.Call.STATE_RINGING -> "incoming"
+            android.telecom.Call.STATE_DIALING, android.telecom.Call.STATE_CONNECTING -> "outgoing"
+            else -> "connected"
+        }
+
+        val call = Call.ExternalCall(
+            telecomCall,
+            ua,
+            uri,
+            if (telecomState == android.telecom.Call.STATE_RINGING) "in" else "out",
+            initialStatus
+        )
+
+        telecomCall.registerCallback(object : android.telecom.Call.Callback() {
+            override fun onStateChanged(call: android.telecom.Call, state: Int) {
+                super.onStateChanged(call, state)
+                val newStatus = when (state) {
+                    android.telecom.Call.STATE_RINGING -> "incoming"
+                    android.telecom.Call.STATE_DIALING, android.telecom.Call.STATE_CONNECTING -> "outgoing"
+                    android.telecom.Call.STATE_ACTIVE -> "connected"
+                    android.telecom.Call.STATE_DISCONNECTED -> "closed"
+                    android.telecom.Call.STATE_HOLDING -> {
+                        calls.find { it.callp == call.hashCode().toLong() }?.onhold = true
+                        "connected"
+                    }
+                    else -> "connected"
+                }
+                calls.find { it.callp == call.hashCode().toLong() }?.let {
+                    if (it.status.value != newStatus) {
+                        it.status.value = newStatus
+                        postServiceEvent(ServiceEvent(
+                            "call update",
+                            arrayListOf(it.ua.uap, it.callp),
+                            System.nanoTime())
+                        )
+                        if (newStatus == "closed")
+                            handleExternalCallRemoved(call)
+                    }
+                }
+            }
+        })
+
+        calls.add(call)
+        postServiceEvent(ServiceEvent(
+            "call incoming",
+            arrayListOf(ua.uap, call.callp),
+            System.nanoTime())
+        )
+    }
+
+    fun handleExternalCallRemoved(telecomCall: android.telecom.Call) {
+        val callp = telecomCall.hashCode().toLong()
+        calls.removeAll { it.callp == callp }
+        messageUpdate.postValue(System.currentTimeMillis())
+    }
+
     private fun toast(message: String, length: Int = Toast.LENGTH_SHORT) {
         Handler(Looper.getMainLooper()).post {
             Toast.makeText(this@BaresipService.applicationContext, message, length).show()

app/src/main/kotlin/com/tutpro/baresip/Call.kt

@@ -8,7 +8,7 @@ import androidx.compose.runtime.mutableStateOf
 import androidx.core.net.toUri
 import java.util.*
 
-class Call(val callp: Long, val ua: UserAgent, val peerUri: String, val dir: String, initialStatus: String) {
+open class Call(val callp: Long, val ua: UserAgent, val peerUri: String, val dir: String, initialStatus: String) {
 
     var status: MutableState<String> = mutableStateOf(initialStatus)
 
@@ -55,11 +55,11 @@ class Call(val callp: Long, val ua: UserAgent, val peerUri: String, val dir: Str
         BaresipService.calls.remove(this)
     }
 
-    fun connect(uri: String): Boolean {
+    open fun connect(uri: String): Boolean {
         return Api.call_connect(callp, uri) == 0
     }
 
-    fun hold(): Boolean {
+    open fun hold(): Boolean {
         if (onhold) return true
         if (Api.call_hold(callp, true)) {
             onhold = true
@@ -71,7 +71,7 @@ class Call(val callp: Long, val ua: UserAgent, val peerUri: String, val dir: Str
         return false
     }
 
-    fun resume(): Boolean {
+    open fun resume(): Boolean {
         if (!onhold && !held) return true
         // 1. Hold other calls first
         for (c in BaresipService.calls) {
@@ -94,13 +94,13 @@ class Call(val callp: Long, val ua: UserAgent, val peerUri: String, val dir: Str
         return false
     }
 
-    fun transfer(uri: String): Boolean {
+    open fun transfer(uri: String): Boolean {
         if (!onhold) hold()
         Log.d(TAG, "Transferring call $callp to $uri")
         return Api.call_transfer(callp, uri) == 0
     }
 
-    fun executeTransfer(): Boolean {
+    open fun executeTransfer(): Boolean {
         return if (onHoldCall != null) {
             if (Api.call_hold(callp, true))
                 Api.call_replace_transfer(onHoldCall!!.callp, callp)
@@ -110,31 +110,31 @@ class Call(val callp: Long, val ua: UserAgent, val peerUri: String, val dir: Str
             false
     }
 
-    fun sendDigit(digit: Char): Int {
+    open fun sendDigit(digit: Char): Int {
         return Api.call_send_digit(callp, digit)
     }
 
-    fun notifySipfrag(code: Int, reason: String) {
+    open fun notifySipfrag(code: Int, reason: String) {
         Api.call_notify_sipfrag(callp, code, reason)
     }
 
-    fun duration(): Int {
+    open fun duration(): Int {
         return Api.call_duration(callp)
     }
 
-    fun stats(stream: String): String {
+    open fun stats(stream: String): String {
         return Api.call_stats(callp, stream)
     }
 
-    fun state(): Int {
+    open fun state(): Int {
         return Api.call_state(callp)
     }
 
-    fun audioCodecs(): String {
+    open fun audioCodecs(): String {
         return Api.call_audio_codecs(callp)
     }
 
-    fun replaces(): Boolean {
+    open fun replaces(): Boolean {
         return Api.call_replaces(callp)
     }
 
@@ -146,10 +146,53 @@ class Call(val callp: Long, val ua: UserAgent, val peerUri: String, val dir: Str
         if (ua.account.mediaEnc != "") security = R.color.colorTrafficRed
     }
 
-    fun destroy() {
+    open fun destroy() {
         Api.call_destroy(callp)
     }
 
+    class ExternalCall(
+        val telecomCall: android.telecom.Call,
+        ua: UserAgent,
+        peerUri: String,
+        dir: String,
+        initialStatus: String
+    ) : Call(telecomCall.hashCode().toLong(), ua, peerUri, dir, initialStatus) {
+
+        override fun connect(uri: String): Boolean {
+            telecomCall.answer(android.telecom.VideoProfile.STATE_AUDIO_ONLY)
+            return true
+        }
+
+        override fun hold(): Boolean {
+            telecomCall.hold()
+            onhold = true
+            callOnHold.value = true
+            return true
+        }
+
+        override fun resume(): Boolean {
+            telecomCall.unhold()
+            onhold = false
+            callOnHold.value = false
+            return true
+        }
+
+        override fun destroy() {
+            telecomCall.disconnect()
+        }
+
+        override fun sendDigit(digit: Char): Int {
+            telecomCall.playDtmfTone(digit)
+            telecomCall.stopDtmfTone()
+            return 0
+        }
+
+        override fun duration(): Int = 0
+        override fun stats(stream: String): String = ""
+        override fun state(): Int = 0
+        override fun audioCodecs(): String = "PSTN"
+    }
+
     companion object {
 
         fun calls(): ArrayList<Call> {

app/src/main/kotlin/com/tutpro/baresip/ConnectionService.kt

@@ -1,6 +1,7 @@
 package com.tutpro.baresip
 
 import android.content.Intent
+import android.net.Uri
 import android.telecom.CallAudioState
 import android.telecom.Connection
 import android.telecom.ConnectionRequest
@@ -8,7 +9,6 @@ import android.telecom.ConnectionService
 import android.telecom.DisconnectCause
 import android.telecom.PhoneAccountHandle
 import android.telecom.TelecomManager
-import android.net.Uri
 import java.util.concurrent.ConcurrentHashMap
 
 class ConnectionService : ConnectionService() {
@@ -64,7 +64,8 @@ class ConnectionService : ConnectionService() {
 
         val connection = BaresipConnection(uap, callp)
         connections[callp] = connection
-        connection.setAddress(Uri.fromParts("sip", peerUri, null), TelecomManager.PRESENTATION_ALLOWED)
+        connection.setAddress(Uri.fromParts("sip", peerUri, null),
+            TelecomManager.PRESENTATION_ALLOWED)
         connection.connectionCapabilities = Connection.CAPABILITY_SUPPORT_HOLD or
                 Connection.CAPABILITY_HOLD or
                 Connection.CAPABILITY_MERGE_CONFERENCE or
@@ -108,6 +109,9 @@ class ConnectionService : ConnectionService() {
         val conferenceCall = rootExtras?.getBoolean("conferenceCall", false) ?:
         nestedExtras?.getBoolean("conferenceCall") ?: false
 
+        val pstnCall = rootExtras?.getBoolean("pstnCall", false) ?:
+        nestedExtras?.getBoolean("pstnCall") ?: false
+
         val onHoldCallp = rootExtras?.getLong("onHoldCallp", 0L).takeIf { it != 0L }
             ?: nestedExtras?.getLong("onHoldCallp") ?: 0L
 
@@ -123,20 +127,15 @@ class ConnectionService : ConnectionService() {
                 Connection.CAPABILITY_HOLD or
                 Connection.CAPABILITY_MERGE_CONFERENCE or
                 Connection.CAPABILITY_SWAP_CONFERENCE
-        connection.audioModeIsVoip = true
 
-        // Start the SIP connection logic
+        if (!pstnCall) {
-        if (uap != 0L) {
+            connection.audioModeIsVoip = true
             val sipUri = if (destination.startsWith("sip:")) destination else "sip:$destination"
             BaresipService.instance?.runCall(uap, sipUri, conferenceCall, onHoldCallp)
-        } else {
-            Log.e(TAG, "Cannot start outgoing call: uap is 0")
-            connection.setDisconnected(DisconnectCause(DisconnectCause.ERROR, "No Account"))
-            connection.destroy()
-            pendingOutgoingConnection = null
         }
 
         connection.setDialing()
+
         return connection
     }
 

app/src/main/kotlin/com/tutpro/baresip/InCallService.kt

@@ -1,24 +1,35 @@
 package com.tutpro.baresip
 
-import android.app.Service
-import android.content.Intent
-import android.os.IBinder
-
-// This is needed in order to allow choosing baresip as default Phone app
-class InCallService : Service() {
-    override fun onBind(intent: Intent): IBinder? {
-        Log.d(TAG, "InCallService onBind with intent: ${intent.action}")
-        return null
-    }
-}
-
-/*import android.telecom.InCallService
 import android.telecom.Call
+import android.telecom.InCallService
 
 class InCallService : InCallService() {
+
     override fun onCallAdded(call: Call) {
         super.onCallAdded(call)
-        // This is triggered when the system wants YOU to show the call UI
+        Log.d(TAG, "InCallService: Call added")
-        Log.d("Baresip", "InCallService: Call added")
+
+        val handle = call.details.accountHandle
+        val baresipHandle = BaresipService.getPhoneAccountHandle(this)
+
+        if (handle == baresipHandle) {
+            Log.d(TAG, "InCallService: Identified as SIP call")
+            // The SIP call is already managed by ConnectionService/BaresipService.
+            // We just need to ensure the InCallService stays bound.
+        } else {
+            Log.d(TAG, "InCallService: Identified as PSTN call from $handle")
+            // This is a cellular call. We need to wrap it so MainScreen can show it.
+            BaresipService.instance?.handleExternalCall(call)
+        }
     }
-}*/
+
+    override fun onCallRemoved(call: Call) {
+        super.onCallRemoved(call)
+        Log.d(TAG, "InCallService: Call removed")
+        BaresipService.instance?.handleExternalCallRemoved(call)
+    }
+
+    companion object {
+        private const val TAG = "Baresip"
+    }
+}

app/src/main/kotlin/com/tutpro/baresip/MainScreen.kt

@@ -12,12 +12,14 @@ import android.content.res.Configuration
 import android.media.AudioManager
 import android.net.Uri
 import android.os.Build.VERSION
+import android.os.Bundle
 import android.os.Handler
 import android.os.Looper
 import android.os.Process
 import android.os.SystemClock
 import android.provider.DocumentsContract
 import android.provider.MediaStore
+import android.telecom.TelecomManager
 import android.widget.Toast
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
@@ -1473,12 +1475,14 @@ private fun CallRow(
         horizontalArrangement = Arrangement.Absolute.SpaceBetween
     ) {
         if (isDialer) {
+            dialerState.showCallPstnButton.value = Utils.pstnAccountHandle(ctx) != null
             if (dialerState.showCallButton.value)
                 IconButton(
                     modifier = Modifier.size(48.dp),
                     enabled = dialerState.callButtonsEnabled.value,
                     onClick = {
                         if (!dialerState.callButtonsEnabled.value) return@IconButton
+                        dialerState.showCallPstnButton.value = false
                         dialerState.showCallConferenceButton.value = false
                         dialerState.showSuggestions.value = false
                         callClick(ctx, viewModel, dialerState)
@@ -1494,6 +1498,28 @@ private fun CallRow(
                         contentDescription = null,
                     )
                 }
+            if (dialerState.showCallPstnButton.value)
+                IconButton(
+                    modifier = Modifier.size(48.dp),
+                    enabled = dialerState.callButtonsEnabled.value,
+                    onClick = {
+                        if (!dialerState.callButtonsEnabled.value) return@IconButton
+                        dialerState.showCallButton.value = false
+                        dialerState.showCallConferenceButton.value = false
+                        dialerState.showSuggestions.value = false
+                        callClick(ctx, viewModel, dialerState)
+                    },
+                ) {
+                    Icon(
+                        imageVector = ImageVector.vectorResource(R.drawable.call_tel),
+                        modifier = Modifier.size(42.dp),
+                        tint = colorResource(if (dialerState.callButtonsEnabled.value)
+                            R.color.colorTrafficGreen
+                        else
+                            R.color.colorTrafficYellow),
+                        contentDescription = null,
+                    )
+                }
             if (dialerState.showCallConferenceButton.value) {
                 Spacer(modifier = Modifier.weight(1f, true))
                 IconButton(
@@ -1502,6 +1528,7 @@ private fun CallRow(
                     onClick = {
                         if (!dialerState.callButtonsEnabled.value) return@IconButton
                         dialerState.showCallButton.value = false
+                        dialerState.showCallPstnButton.value = false
                         dialerState.showSuggestions.value = false
                         callClick(ctx, viewModel, dialerState)
                     }
@@ -2061,14 +2088,14 @@ private fun callClick(ctx: Context, viewModel: ViewModel, dialerState: ViewModel
                         ctx,
                         viewModel,
                         uriText,
-                        dialerState.showCallConferenceButton.value
+                        dialerState
                     )
                 else if (uris.size == 1)
                     makeCall(
                         ctx,
                         viewModel,
                         uris[0],
-                        dialerState.showCallConferenceButton.value
+                        dialerState
                     )
                 else {
                     selectItems.value = uris
@@ -2077,7 +2104,7 @@ private fun callClick(ctx: Context, viewModel: ViewModel, dialerState: ViewModel
                             ctx,
                             viewModel,
                             uris[index],
-                            dialerState.showCallConferenceButton.value
+                            dialerState
                         )
                     }
                     showSelectItemDialog.value = true
@@ -2095,8 +2122,8 @@ private fun callClick(ctx: Context, viewModel: ViewModel, dialerState: ViewModel
     }
 }
 
-private fun makeCall(ctx: Context, viewModel: ViewModel, uriText: String, conferenceCall: Boolean,
+private fun makeCall(ctx: Context, viewModel: ViewModel, uriText: String,
-                     onHoldCallp: Long = 0L) {
+                     dialerState: ViewModel.DialerState, onHoldCallp: Long = 0L) {
     val aor = viewModel.selectedAor.value
     val ua = UserAgent.ofAor(aor)!!
     val peerUri = if (Utils.isTelNumber(uriText))
@@ -2104,13 +2131,16 @@ private fun makeCall(ctx: Context, viewModel: ViewModel, uriText: String, confer
     else
         uriText
     val uri = if (Utils.isTelUri(peerUri)) {
-        if (ua.account.telProvider == "") {
+        if (dialerState.showCallPstnButton.value)
+            peerUri
+        else if (ua.account.telProvider == "") {
             alertTitle.value = ctx.getString(R.string.notice)
             alertMessage.value = String.format(ctx.getString(R.string.no_telephony_provider), aor)
             showAlert.value = true
             return
         }
-        Utils.telToSip(peerUri, ua.account)
+        else
+            Utils.telToSip(peerUri, ua.account)
     }
     else
         Utils.uriComplete(peerUri, aor)
@@ -2118,28 +2148,62 @@ private fun makeCall(ctx: Context, viewModel: ViewModel, uriText: String, confer
         alertTitle.value = ctx.getString(R.string.notice)
         alertMessage.value = String.format(ctx.getString(R.string.invalid_sip_or_tel_uri), uri)
         showAlert.value = true
+        return
+    }
+    else if (dialerState.showCallPstnButton.value && !Utils.isTelUri(uri)) {
+            alertTitle.value = ctx.getString(R.string.notice)
+            alertMessage.value = "Telephone call can only be made to telephone number"
+            showAlert.value = true
+            return
     }
     else if (Utils.isAudioMode(ctx,AudioManager.MODE_IN_CALL) &&
             !Call.calls().any { it.ua.account.aor == ua.account.aor })
         Toast.makeText(ctx, R.string.call_already_active, Toast.LENGTH_SHORT).show()
     else {
         viewModel.dialerState.callButtonsEnabled.value = false
+        var error = ""
         if (BaresipService.telecom) {
-            val tm = ctx.getSystemService(Context.TELECOM_SERVICE) as android.telecom.TelecomManager
+            val tm = ctx.getSystemService(Context.TELECOM_SERVICE) as TelecomManager
-            val extras = android.os.Bundle()
+            if (dialerState.showCallPstnButton.value) {
-            extras.putParcelable(android.telecom.TelecomManager.EXTRA_PHONE_ACCOUNT_HANDLE,
+                val phoneAccountHandle = Utils.pstnAccountHandle(ctx)
-                BaresipService.getPhoneAccountHandle(ctx))
+                if (phoneAccountHandle != null) {
-            val callExtras = android.os.Bundle()
+                    val extras = Bundle().apply {
-            callExtras.putBoolean("conferenceCall", conferenceCall)
+                        putParcelable(TelecomManager.EXTRA_PHONE_ACCOUNT_HANDLE, phoneAccountHandle)
-            callExtras.putLong("uap", ua.uap)
+                    }
-            if (onHoldCallp != 0L)
+                    val callExtras = Bundle()
-                callExtras.putLong("onHoldCallp", onHoldCallp)
+                    callExtras.putBoolean("pstnCall", dialerState.showCallPstnButton.value)
-            extras.putBundle(android.telecom.TelecomManager.EXTRA_OUTGOING_CALL_EXTRAS, callExtras)
+                    extras.putBundle(TelecomManager.EXTRA_OUTGOING_CALL_EXTRAS, callExtras)
-            try {
+                    try {
-                Log.d(TAG, "Placing Telecom call to $uri with uap=${ua.uap}")
+                        Log.i(TAG, "Placing Telecom PSTN call to $uri with uap=${ua.uap}")
-                tm.placeCall(uri.toUri(), extras)
+                        tm.placeCall(uri.toUri(), extras)
-            } catch (e: SecurityException) {
+                    } catch (e: SecurityException) {
-                Log.e(TAG, "placeCall failed: ${e.message}")
+                        error = "placeCall failed: ${e.message}"
+                    }
+                }
+                else
+                    error = "no phone account"
+            }
+            else {
+                val extras = Bundle()
+                extras.putParcelable(
+                    TelecomManager.EXTRA_PHONE_ACCOUNT_HANDLE,
+                    BaresipService.getPhoneAccountHandle(ctx)
+                )
+                val callExtras = Bundle()
+                callExtras.putBoolean("conferenceCall", dialerState.showCallConferenceButton.value)
+                callExtras.putLong("uap", ua.uap)
+                if (onHoldCallp != 0L)
+                    callExtras.putLong("onHoldCallp", onHoldCallp)
+                extras.putBundle(TelecomManager.EXTRA_OUTGOING_CALL_EXTRAS, callExtras)
+                try {
+                    Log.d(TAG, "Placing Telecom SIP call to $uri with uap=${ua.uap}")
+                    tm.placeCall(uri.toUri(), extras)
+                } catch (e: SecurityException) {
+                    error = "placeCall failed: ${e.message}"
+                }
+            }
+            if (error != "") {
+                Log.e(TAG, error)
                 viewModel.dialerState.callButtonsEnabled.value = true
             }
         }
@@ -2148,7 +2212,7 @@ private fun makeCall(ctx: Context, viewModel: ViewModel, uriText: String, confer
             intent.action = "Start Call"
             intent.putExtra("uap", ua.uap)
             intent.putExtra("uri", uri)
-            intent.putExtra("conferenceCall", conferenceCall)
+            intent.putExtra("conferenceCall", dialerState.showCallConferenceButton.value)
             intent.putExtra("onHoldCallp", onHoldCallp)
             ctx.startService(intent)
         }
@@ -2207,7 +2271,7 @@ private fun transfer(ctx: Context, viewModel: ViewModel, ua: UserAgent, uriText:
                 if (success) {
                     call.onhold = true
                     call.referTo = uri
-                    makeCall(ctx, viewModel, uri, false, call.callp)
+                    makeCall(ctx, viewModel, uri, viewModel.dialerState, call.callp)
                     showCall(ctx, viewModel, ua, call)
                 }
             }
@@ -2237,6 +2301,7 @@ private fun showCall(ctx: Context, viewModel: ViewModel, ua: UserAgent?, showCal
             viewModel.dialerState.callUriEnabled.value = true
         }, 100)
         viewModel.dialerState.showCallButton.value = true
+        viewModel.dialerState.showCallPstnButton.value = true
         viewModel.dialerState.showCallConferenceButton.value = true
         viewModel.dialerState.callButtonsEnabled.value = true
         viewModel.dialerState.showSuggestions.value = false
@@ -2521,7 +2586,7 @@ fun handleServiceEvent(ctx: Context, viewModel: ViewModel, event: String, params
                 if (call in Call.calls())
                     acceptTransfer(ctx, viewModel, ua, call!!, ev[1])
                 else
-                    makeCall(ctx, viewModel, ev[1], false)
+                    makeCall(ctx, viewModel, ev[1], viewModel.dialerState)
             }
             showDialog.value = true
         }
@@ -2530,7 +2595,7 @@ fun handleServiceEvent(ctx: Context, viewModel: ViewModel, event: String, params
             val call = Call.ofCallp(callp)
             if (call in Call.calls())
                 Api.ua_hangup(uap, callp, 487, "Request Terminated")
-            makeCall(ctx, viewModel, ev[1], false)
+            makeCall(ctx, viewModel, ev[1], viewModel.dialerState)
             showCall(ctx, viewModel, ua)
         }
         "transfer failed" -> {

app/src/main/kotlin/com/tutpro/baresip/Utils.kt

@@ -1,5 +1,6 @@
 package com.tutpro.baresip
 
+import android.Manifest
 import android.annotation.SuppressLint
 import android.app.Activity
 import android.app.KeyguardManager
@@ -1323,6 +1324,26 @@ object Utils {
         return file
     }
 
+    fun pstnAccountHandle(ctx: Context):  PhoneAccountHandle? {
+        if (ctx.checkSelfPermission(Manifest.permission.READ_PHONE_STATE) ==
+                PackageManager.PERMISSION_GRANTED) {
+            val tm = ctx.getSystemService(Context.TELECOM_SERVICE) as TelecomManager
+            if (Build.VERSION.SDK_INT >= 29) {
+                val preferredHandle: PhoneAccountHandle? = tm.userSelectedOutgoingPhoneAccount
+                if (preferredHandle != null)
+                    return preferredHandle
+            }
+            val baresipHandle = BaresipService.getPhoneAccountHandle(ctx)
+            val phoneAccounts = tm.callCapablePhoneAccounts.filter { it != baresipHandle }
+            return if (phoneAccounts.isNotEmpty())
+                phoneAccounts[0]
+            else
+                null
+        }
+        else
+            return null
+    }
+
     @Suppress("unused")
     fun listFilesInDirectory(directoryPath: String): List<File> {
         val directory = File(directoryPath)

app/src/main/kotlin/com/tutpro/baresip/ViewModel.kt

@@ -44,6 +44,7 @@ class ViewModel: ViewModel() {
         val callUriLabel: MutableState<String> = mutableStateOf(""),
         val showSuggestions: MutableState<Boolean> = mutableStateOf(false),
         val showCallButton: MutableState<Boolean> = mutableStateOf(true),
+        val showCallPstnButton: MutableState<Boolean> = mutableStateOf(true),
         val showCallConferenceButton: MutableState<Boolean> = mutableStateOf(true),
         val callButtonsEnabled: MutableState<Boolean> = mutableStateOf(true),
         val conferenceCall: MutableState<Boolean> = mutableStateOf(false),

app/src/main/res/drawable/call_tel.xml

@@ -0,0 +1,32 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="960"
+    android:viewportHeight="960"
+    android:tint="?attr/colorControlNormal">
+
+    <!-- Phone handle -->
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="
+            M798,840Q673,840 551,785.5Q429,731 329,631Q229,531 174.5,409Q120,287 120,162Q120,144 132,132Q144,120 162,120L324,120Q338,120 349,129.5Q360,139 362,152L388,292Q390,308 387,319Q384,330 376,338L279,436Q299,473 326.5,507.5Q354,542 387,574Q418,605 452,631.5Q486,658 524,680L618,586Q627,577 641.5,572.5Q656,568 670,570L808,598Q822,602 831,612.5Q840,623 840,636L840,798Q840,816 828,828Q816,840 798,840ZM241,360L307,294L290,200L201,200Q206,241 215,281Q224,321 241,360ZM599,718Q638,735 678.5,745Q719,755 760,758L760,670L666,651L599,718Z" />
+
+    <!-- Letter T -->
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="
+            M480,120L600,120L600,160L560,160L560,320L520,320L520,160L480,160Z" />
+
+    <!-- Letter E -->
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="
+            M620,120L740,120L740,160L660,160L660,200L730,200L730,240L660,240L660,280L740,280L740,320L620,320Z" />
+
+    <!-- Letter L -->
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="
+            M760,120L800,120L800,280L860,280L860,320L760,320Z" />
+
+</vector>