From 110824e73b4addf64db11b2ba9428529d0b6a7a9 Mon Sep 17 00:00:00 2001
From: Bryan Biedenkapp <gatekeep@gmail.com>
Date: Fri, 21 Mar 2025 11:50:47 -0400
Subject: [PATCH] fix implementation for acking Start of Stream (writeImmediate
 wasn't really necessary using STT_NON_IMBE_NO_JITTER causes queued packets to
 bypass jitter buffer timing);

---
 src/host/modem/ModemV24.cpp | 35 ++++++++++-------------------------
 src/host/modem/ModemV24.h   |  8 --------
 2 files changed, 10 insertions(+), 33 deletions(-)

diff --git a/src/host/modem/ModemV24.cpp b/src/host/modem/ModemV24.cpp
index 2818c8f9..f8d6e338 100644
--- a/src/host/modem/ModemV24.cpp
+++ b/src/host/modem/ModemV24.cpp
@@ -1178,6 +1178,15 @@ void ModemV24::convertToAirTIA(const uint8_t *data, uint32_t length)
         }
         break;
 
+        case BlockType::START_OF_STREAM_ACK:
+        {
+            if (m_debug)
+                ::LogDebugEx(LOG_MODEM, "ModemV24::convertToAirTIA()", "Start of Stream ACK");
+
+            // do nothing with the start of stream ack
+        }
+        break;
+
         case BlockType::VOICE_HEADER_P1:
         {
             // copy to call data VHDR1
@@ -1942,7 +1951,7 @@ void ModemV24::ackStartOfStreamTIA()
     if (m_trace)
         Utils::dump(1U, "ModemV24::ackStartOfStreamTIA() Ack StartOfStream", buffer, length);
 
-    writeImmediate(buffer, length);
+    queueP25Frame(buffer, length, STT_NON_IMBE_NO_JITTER);
 }
 
 /* Internal helper to convert from TIA-102 air interface to V.24/DFSI. */
@@ -2570,27 +2579,3 @@ void ModemV24::convertFromAirTIA(uint8_t* data, uint32_t length)
         }
     }
 }
-
-/* Writes raw data to the air interface modem. */
-
-int ModemV24::writeImmediate(const uint8_t* data, uint32_t length)
-{
-    assert(data != nullptr);
-
-    // add the DVM start byte, length byte, CMD byte, and padding 0
-    uint8_t header[4U];
-    header[0U] = DVM_SHORT_FRAME_START;
-    header[1U] = length & 0xFFU;
-    header[2U] = CMD_P25_DATA;
-    header[3U] = 0x00U;
-    
-    // get the actual data
-    UInt8Array __buffer = std::make_unique<uint8_t[]>(length + 4U);
-    uint8_t* buffer = __buffer.get();
-
-    ::memset(buffer, 0x00U, length + 4U);
-    ::memcpy(buffer, header, 4U);
-    ::memcpy(buffer + 4U, data, length);
-
-    return m_port->write(data, length);
-}
diff --git a/src/host/modem/ModemV24.h b/src/host/modem/ModemV24.h
index 04f93aab..f4069f91 100644
--- a/src/host/modem/ModemV24.h
+++ b/src/host/modem/ModemV24.h
@@ -408,14 +408,6 @@ namespace modem
          * @param length Length of buffer.
          */
         void convertFromAirTIA(uint8_t* data, uint32_t length);
-
-        /**
-         * @brief Writes raw data to the air interface modem (with no jitter delay).
-         * @param data Data to write to modem.
-         * @param length Length of data to write.
-         * @returns int Actual length of data written.
-         */
-        int writeImmediate(const uint8_t* data, uint32_t length);
     };
 } // namespace modem