diff --git a/config.example.yml b/config.example.yml
index 349f8e8f..ff09bc4b 100644
--- a/config.example.yml
+++ b/config.example.yml
@@ -68,6 +68,7 @@ protocols:
         callHang: 5
         noStatusAck: false
         noMessageAck: true
+        unitToUnitAvailCheck: true
         silenceThreshold: 124
         disableNetworkHDU: false
         queueSize: 5000
diff --git a/p25/Control.cpp b/p25/Control.cpp
index e13cdd30..b3b4db09 100644
--- a/p25/Control.cpp
+++ b/p25/Control.cpp
@@ -200,6 +200,7 @@ void Control::setOptions(yaml::Node& conf, const std::string cwCallsign, const s
 
     m_trunk->m_noStatusAck = p25Protocol["noStatusAck"].as<bool>(false);
     m_trunk->m_noMessageAck = p25Protocol["noMessageAck"].as<bool>(true);
+    m_trunk->m_unitToUnitAvailCheck = p25Protocol["unitToUnitAvailCheck"].as<bool>(true);
 
     yaml::Node control = p25Protocol["control"];
     m_control = control["enable"].as<bool>(false);
@@ -275,6 +276,7 @@ void Control::setOptions(yaml::Node& conf, const std::string cwCallsign, const s
 
         LogInfo("    No Status ACK: %s", m_trunk->m_noStatusAck ? "yes" : "no");
         LogInfo("    No Message ACK: %s", m_trunk->m_noMessageAck ? "yes" : "no");
+        LogInfo("    Unit-to-Unit Availability Check: %s", m_trunk->m_unitToUnitAvailCheck ? "yes" : "no");
     }
 
     m_voice->resetRF();
diff --git a/p25/P25Defines.h b/p25/P25Defines.h
index 7940848c..09503f02 100644
--- a/p25/P25Defines.h
+++ b/p25/P25Defines.h
@@ -181,6 +181,8 @@ namespace p25
     const uint32_t  P25_DENY_RSN_PTT_BONK = 0x77U;
     const uint32_t  P25_DENY_RSN_SYS_UNSUPPORTED_SVC = 0xFFU;
 
+    const uint32_t  P25_QUE_RSN_REQ_ACTIVE_SERVICE = 0x10U;
+    const uint32_t  P25_QUE_RSN_TGT_ACTIVE_SERVICE = 0x20U;
     const uint32_t  P25_QUE_RSN_TGT_UNIT_QUEUED = 0x2FU;
     const uint32_t  P25_QUE_RSN_CHN_RESOURCE_NOT_AVAIL = 0x40U;
 
diff --git a/p25/TrunkPacket.cpp b/p25/TrunkPacket.cpp
index cd31abfb..e10d8710 100644
--- a/p25/TrunkPacket.cpp
+++ b/p25/TrunkPacket.cpp
@@ -236,7 +236,12 @@ bool TrunkPacket::process(uint8_t* data, uint32_t len)
                     LogMessage(LOG_RF, P25_TSDU_STR ", TSBK_IOSP_UU_VCH (Unit-to-Unit Voice Channel Request), srcId = %u, dstId = %u", srcId, dstId);
                 }
 
-                writeRF_TSDU_UU_Ans_Req(srcId, dstId);
+                if (m_unitToUnitAvailCheck) {
+                    writeRF_TSDU_UU_Ans_Req(srcId, dstId);
+                }
+                else {
+                    writeRF_TSDU_Grant(false, false, false);
+                }
                 break;
             case TSBK_IOSP_UU_ANS:
                 // make sure control data is supported
@@ -253,10 +258,6 @@ bool TrunkPacket::process(uint8_t* data, uint32_t len)
                         m_rfTSBK.getResponse(), srcId, dstId);
                 }
 
-                if (m_p25->m_ackTSBKRequests) {
-                    writeRF_TSDU_ACK_FNE(srcId, TSBK_IOSP_UU_ANS, false, true);
-                }
-
                 if (m_rfTSBK.getResponse() == P25_ANS_RSP_PROCEED) {
                     writeRF_TSDU_Grant(false, false, false);
                 }
@@ -283,16 +284,7 @@ bool TrunkPacket::process(uint8_t* data, uint32_t len)
                     writeRF_TSDU_ACK_FNE(srcId, TSBK_IOSP_TELE_INT_ANS, false, true);
                 }
 
-                if (m_rfTSBK.getResponse() == P25_ANS_RSP_PROCEED) {
-                    //writeRF_TSDU_Grant(false);
-                    writeRF_TSDU_Deny(P25_DENY_RSN_SYS_UNSUPPORTED_SVC, TSBK_IOSP_TELE_INT_ANS);
-                }
-                else if (m_rfTSBK.getResponse() == P25_ANS_RSP_DENY) {
-                    writeRF_TSDU_ACK_FNE(srcId, TSBK_IOSP_TELE_INT_ANS, false, true);
-                }
-                else if (m_rfTSBK.getResponse() == P25_ANS_RSP_WAIT) {
-                    writeRF_TSDU_Queue(P25_QUE_RSN_TGT_UNIT_QUEUED, TSBK_IOSP_TELE_INT_ANS);
-                }
+                writeRF_TSDU_Deny(P25_DENY_RSN_SYS_UNSUPPORTED_SVC, TSBK_IOSP_TELE_INT_ANS);
                 break;
             case TSBK_ISP_SNDCP_CH_REQ:
                 // make sure control data is supported
@@ -420,7 +412,7 @@ bool TrunkPacket::process(uint8_t* data, uint32_t len)
 
                     ::ActivityLog("P25", true, "emergency alarm request request from %u", srcId);
 
-                    writeRF_TSDU_SBF(false);
+                    writeRF_TSDU_ACK_FNE(srcId, TSBK_ISP_EMERG_ALRM_REQ, false, true);
                 }
                 break;
             case TSBK_IOSP_GRP_AFF:
@@ -1214,6 +1206,7 @@ TrunkPacket::TrunkPacket(Control* p25, network::BaseNetwork* network, bool dumpT
     m_voiceGrantChCnt(0U),
     m_noStatusAck(false),
     m_noMessageAck(true),
+    m_unitToUnitAvailCheck(true),
     m_adjSiteUpdateTimer(1000U),
     m_adjSiteUpdateInterval(ADJ_SITE_TIMER_TIMEOUT),
     m_ctrlTSDUMBF(true),
diff --git a/p25/TrunkPacket.h b/p25/TrunkPacket.h
index f94e9052..772716ae 100644
--- a/p25/TrunkPacket.h
+++ b/p25/TrunkPacket.h
@@ -150,6 +150,7 @@ namespace p25
 
         bool m_noStatusAck;
         bool m_noMessageAck;
+        bool m_unitToUnitAvailCheck;
 
         Timer m_adjSiteUpdateTimer;
         uint32_t m_adjSiteUpdateInterval;