diff --git a/gui/package.json b/gui/package.json
index 86b33123..4f3f85fa 100644
--- a/gui/package.json
+++ b/gui/package.json
@@ -2,7 +2,7 @@
   "name": "FreeDATA",
   "description": "FreeDATA Client application for connecting to FreeDATA server",
   "private": true,
-  "version": "0.14.4-alpha",
+  "version": "0.14.5-alpha",
   "main": "dist-electron/main/index.js",
   "scripts": {
     "start": "vite",
@@ -77,7 +77,7 @@
     "vite": "5.1.3",
     "vite-plugin-electron": "0.28.2",
     "vite-plugin-electron-renderer": "0.14.5",
-    "vitest": "1.2.2",
+    "vitest": "1.3.1",
     "vue": "3.4.21",
     "vue-tsc": "1.8.27"
   }
diff --git a/gui/src/components/main.vue b/gui/src/components/main.vue
index 8375c71a..ab0a861c 100644
--- a/gui/src/components/main.vue
+++ b/gui/src/components/main.vue
@@ -124,7 +124,6 @@ import { loadAllData } from "../js/eventHandler";
               <!-------------------------------- MAIN AREA ---------------->
 
               <!------------------------------------------------------------------------------------------>
-
             </div>
           </div>
 
diff --git a/gui/src/components/settings_modem.vue b/gui/src/components/settings_modem.vue
index 3b86f397..a7abd922 100644
--- a/gui/src/components/settings_modem.vue
+++ b/gui/src/components/settings_modem.vue
@@ -165,20 +165,20 @@ const audioStore = useAudioStore();
   </div>
 
   <div class="input-group input-group-sm mb-1">
-    <label class="input-group-text w-50">Enable 250Hz bandwidth mode</label>
-    <label class="input-group-text w-50">
-      <div class="form-check form-switch form-check-inline">
-        <input
-          class="form-check-input"
-          type="checkbox"
-          id="250HzModeSwitch"
-          v-model="settings.remote.MODEM.enable_low_bandwidth_mode"
-          @change="onChange"
-        />
-        <label class="form-check-label" for="250HzModeSwitch">250Hz</label>
-      </div>
-    </label>
+    <label class="input-group-text w-50">Maximum used bandwidth</label>
+    <select
+      class="form-select form-select-sm"
+      id="maximum_bandwidth"
+      @change="onChange"
+      v-model.number="settings.remote.MODEM.maximum_bandwidth"
+    >
+      <option value="250">250 Hz</option>
+      <option value="563">563 Hz</option>
+      <option value="1700">1700 Hz</option>
+    </select>
   </div>
+
+
   <div class="input-group input-group-sm mb-1">
     <label class="input-group-text w-50">Respond to CQ</label>
     <label class="input-group-text w-50">
diff --git a/gui/src/store/settingsStore.js b/gui/src/store/settingsStore.js
index b1441d31..945b7358 100644
--- a/gui/src/store/settingsStore.js
+++ b/gui/src/store/settingsStore.js
@@ -54,11 +54,11 @@ const defaultConfig = {
       enable_protocol: false,
     },
     MODEM: {
-      enable_low_bandwidth_mode: false,
       respond_to_cq: false,
       tx_delay: 0,
       enable_hamc: false,
       enable_morse_identifier: false,
+      maximum_bandwidth: 3000,
     },
     RADIO: {
       control: "disabled",
diff --git a/modem/arq_session.py b/modem/arq_session.py
index 0db45356..a6cfcf8b 100644
--- a/modem/arq_session.py
+++ b/modem/arq_session.py
@@ -1,5 +1,5 @@
 import datetime
-import queue, threading
+import threading
 import codec2
 import data_frame_factory
 import structlog
@@ -9,23 +9,26 @@ import time
 from arq_data_type_handler import ARQDataTypeHandler
 
 
-class ARQSession():
+class ARQSession:
 
     SPEED_LEVEL_DICT = {
         0: {
             'mode': codec2.FREEDV_MODE.datac4,
             'min_snr': -10,
             'duration_per_frame': 5.17,
+            'bandwidth': 250,
         },
         1: {
             'mode': codec2.FREEDV_MODE.datac3,
             'min_snr': 0,
             'duration_per_frame': 3.19,
+            'bandwidth': 563,
         },
         2: {
             'mode': codec2.FREEDV_MODE.datac1,
             'min_snr': 3,
             'duration_per_frame': 4.18,
+            'bandwidth': 1700,
         },
     }
 
@@ -63,7 +66,7 @@ class ARQSession():
         self.bpm_histogram = []
         self.time_histogram = []
 
-    def log(self, message, isWarning = False):
+    def log(self, message, isWarning=False):
         msg = f"[{type(self).__name__}][id={self.id}][state={self.state}]: {message}"
         logger = self.logger.warn if isWarning else self.logger.info
         logger(msg)
@@ -99,21 +102,22 @@ class ARQSession():
         self.event_frame_received.set()
         self.log(f"Received {frame['frame_type']}")
         frame_type = frame['frame_type_int']
-        if self.state in self.STATE_TRANSITION:
-            if frame_type in self.STATE_TRANSITION[self.state]:
-                action_name = self.STATE_TRANSITION[self.state][frame_type]
-                received_data, type_byte = getattr(self, action_name)(frame)
-                if isinstance(received_data, bytearray) and isinstance(type_byte, int):
-                    self.arq_data_type_handler.dispatch(type_byte, received_data, self.update_histograms(len(received_data), len(received_data)))
-                return
+        if self.state in self.STATE_TRANSITION and frame_type in self.STATE_TRANSITION[self.state]:
+            action_name = self.STATE_TRANSITION[self.state][frame_type]
+            received_data, type_byte = getattr(self, action_name)(frame)
+            if isinstance(received_data, bytearray) and isinstance(type_byte, int):
+                self.arq_data_type_handler.dispatch(type_byte, received_data, self.update_histograms(len(received_data), len(received_data)))
+            return
         
         self.log(f"Ignoring unknown transition from state {self.state.name} with frame {frame['frame_type']}")
 
     def is_session_outdated(self):
         session_alivetime = time.time() - self.session_max_age
-        if self.session_ended < session_alivetime and self.state.name in ['FAILED', 'ENDED', 'ABORTED']:
-            return True
-        return False
+        return self.session_ended < session_alivetime and self.state.name in [
+            'FAILED',
+            'ENDED',
+            'ABORTED',
+        ]
 
     def calculate_session_duration(self):
         if self.session_ended == 0:
@@ -123,7 +127,7 @@ class ARQSession():
 
     def calculate_session_statistics(self, confirmed_bytes, total_bytes):
         duration = self.calculate_session_duration()
-        #total_bytes = self.total_length
+        # total_bytes = self.total_length
         # self.total_length
         duration_in_minutes = duration / 60  # Convert duration from seconds to minutes
 
@@ -134,9 +138,9 @@ class ARQSession():
             bytes_per_minute = 0
 
         # Convert histograms lists to dictionaries
-        time_histogram_dict = {i: timestamp for i, timestamp in enumerate(self.time_histogram)}
-        snr_histogram_dict = {i: snr for i, snr in enumerate(self.snr_histogram)}
-        bpm_histogram_dict = {i: bpm for i, bpm in enumerate(self.bpm_histogram)}
+        time_histogram_dict = dict(enumerate(self.time_histogram))
+        snr_histogram_dict = dict(enumerate(self.snr_histogram))
+        bpm_histogram_dict = dict(enumerate(self.bpm_histogram))
 
         return {
             'total_bytes': total_bytes,
@@ -160,11 +164,20 @@ class ARQSession():
 
         return stats
 
-    def get_appropriate_speed_level(self, snr):
-        # Start with the lowest speed level as default
-        # In case of a not fitting SNR, we return the lowest speed level
+    def get_appropriate_speed_level(self, snr, maximum_bandwidth=None):
+        if maximum_bandwidth is None:
+            maximum_bandwidth = self.config['MODEM']['maximum_bandwidth']
+
+        # Adjust maximum_bandwidth based on special conditions or invalid configurations
+        if maximum_bandwidth == 0:
+            # Use the maximum available bandwidth from the speed level dictionary
+            maximum_bandwidth = max(details['bandwidth'] for details in self.SPEED_LEVEL_DICT.values())
+
+        # Initialize appropriate_speed_level to the lowest level that meets the minimum criteria
         appropriate_speed_level = min(self.SPEED_LEVEL_DICT.keys())
+
         for level, details in self.SPEED_LEVEL_DICT.items():
-            if snr >= details['min_snr'] and level > appropriate_speed_level:
+            if snr >= details['min_snr'] and details['bandwidth'] <= maximum_bandwidth and level > appropriate_speed_level:
                 appropriate_speed_level = level
-        return appropriate_speed_level
\ No newline at end of file
+
+        return appropriate_speed_level
diff --git a/modem/arq_session_irs.py b/modem/arq_session_irs.py
index fa6409fb..92bf0d83 100644
--- a/modem/arq_session_irs.py
+++ b/modem/arq_session_irs.py
@@ -18,7 +18,7 @@ class IRS_State(Enum):
 class ARQSessionIRS(arq_session.ARQSession):
 
     TIMEOUT_CONNECT = 55 #14.2
-    TIMEOUT_DATA = 60
+    TIMEOUT_DATA = 120
 
     STATE_TRANSITION = {
         IRS_State.NEW: { 
@@ -76,14 +76,15 @@ class ARQSessionIRS(arq_session.ARQSession):
         self.received_bytes = 0
         self.received_crc = None
 
+        self.maximum_bandwidth = 0
+
         self.abort = False
 
     def all_data_received(self):
         return self.total_length == self.received_bytes
 
     def final_crc_matches(self) -> bool:
-        match = self.total_crc == helpers.get_crc_32(bytes(self.received_data)).hex()
-        return match
+        return self.total_crc == helpers.get_crc_32(bytes(self.received_data)).hex()
 
     def transmit_and_wait(self, frame, timeout, mode):
         self.event_frame_received.clear()
@@ -99,6 +100,12 @@ class ARQSessionIRS(arq_session.ARQSession):
         thread_wait.start()
     
     def send_open_ack(self, open_frame):
+        self.maximum_bandwidth = open_frame['maximum_bandwidth']
+        # check for maximum bandwidth. If ISS bandwidth is higher than own, then use own
+        if open_frame['maximum_bandwidth'] > self.config['MODEM']['maximum_bandwidth']:
+            self.maximum_bandwidth = self.config['MODEM']['maximum_bandwidth']
+
+
         self.event_manager.send_arq_session_new(
             False, self.id, self.dxcall, 0, self.state.name)
         ack_frame = self.frame_factory.build_arq_session_open_ack(
@@ -212,7 +219,7 @@ class ARQSessionIRS(arq_session.ARQSession):
             received_speed_level = 0
 
         latest_snr = self.snr if self.snr else -10
-        appropriate_speed_level = self.get_appropriate_speed_level(latest_snr)
+        appropriate_speed_level = self.get_appropriate_speed_level(latest_snr, self.maximum_bandwidth)
         modes_to_decode = {}
 
         # Log the latest SNR, current, appropriate speed levels, and the previous speed level
@@ -247,7 +254,7 @@ class ARQSessionIRS(arq_session.ARQSession):
         return self.speed_level
 
     def abort_transmission(self):
-        self.log(f"Aborting transmission... setting abort flag")
+        self.log("Aborting transmission... setting abort flag")
         self.abort = True
 
     def send_stop_ack(self, stop_frame):
@@ -263,7 +270,7 @@ class ARQSessionIRS(arq_session.ARQSession):
         # final function for failed transmissions
         self.session_ended = time.time()
         self.set_state(IRS_State.FAILED)
-        self.log(f"Transmission failed!")
+        self.log("Transmission failed!")
         self.event_manager.send_arq_session_finished(True, self.id, self.dxcall,False, self.state.name, statistics=self.calculate_session_statistics(self.received_bytes, self.total_length))
         self.states.setARQ(False)
         return None, None
diff --git a/modem/arq_session_iss.py b/modem/arq_session_iss.py
index 611f591e..12f91d93 100644
--- a/modem/arq_session_iss.py
+++ b/modem/arq_session_iss.py
@@ -1,6 +1,5 @@
 import threading
 import data_frame_factory
-import queue
 import random
 from codec2 import FREEDV_MODE
 from modem_frametypes import FRAME_TYPE
@@ -105,9 +104,10 @@ class ARQSessionISS(arq_session.ARQSession):
         twr.start()
 
     def start(self):
+        maximum_bandwidth = self.config['MODEM']['maximum_bandwidth']
         self.event_manager.send_arq_session_new(
             True, self.id, self.dxcall, self.total_length, self.state.name)
-        session_open_frame = self.frame_factory.build_arq_session_open(self.dxcall, self.id)
+        session_open_frame = self.frame_factory.build_arq_session_open(self.dxcall, self.id, maximum_bandwidth)
         self.launch_twr(session_open_frame, self.TIMEOUT_CONNECT_ACK, self.RETRIES_CONNECT, mode=FREEDV_MODE.signalling)
         self.set_state(ISS_State.OPEN_SENT)
 
@@ -174,7 +174,7 @@ class ARQSessionISS(arq_session.ARQSession):
 
         payload_size = self.get_data_payload_size()
         burst = []
-        for f in range(0, self.frames_per_burst):
+        for _ in range(0, self.frames_per_burst):
             offset = self.confirmed_bytes
             payload = self.data[offset : offset + payload_size]
             data_frame = self.frame_factory.build_arq_burst_frame(
@@ -200,7 +200,7 @@ class ARQSessionISS(arq_session.ARQSession):
         # final function for failed transmissions
         self.session_ended = time.time()
         self.set_state(ISS_State.FAILED)
-        self.log(f"Transmission failed!")
+        self.log("Transmission failed!")
         self.event_manager.send_arq_session_finished(True, self.id, self.dxcall,False, self.state.name, statistics=self.calculate_session_statistics(self.confirmed_bytes, self.total_length))
         self.states.setARQ(False)
 
@@ -209,7 +209,7 @@ class ARQSessionISS(arq_session.ARQSession):
 
     def abort_transmission(self, irs_frame=None):
         # function for starting the abort sequence
-        self.log(f"aborting transmission...")
+        self.log("aborting transmission...")
         self.set_state(ISS_State.ABORTING)
 
         self.event_manager.send_arq_session_finished(
diff --git a/modem/config.ini.example b/modem/config.ini.example
index c8c7dae1..c5cd6c18 100644
--- a/modem/config.ini.example
+++ b/modem/config.ini.example
@@ -45,10 +45,10 @@ enable_protocol = False
 
 [MODEM]
 enable_hmac = False
-enable_low_bandwidth_mode = False
 enable_morse_identifier = False
 respond_to_cq = True
-tx_delay = 200
+tx_delay = 50
+maximum_bandwidth = 1700
 
 [MESSAGES]
 enable_auto_repeat = False
diff --git a/modem/config.py b/modem/config.py
index fa9926df..c131626b 100644
--- a/modem/config.py
+++ b/modem/config.py
@@ -57,7 +57,7 @@ class CONFIG:
         'MODEM': {
             'enable_hmac': bool,
             'enable_morse_identifier': bool,
-            'enable_low_bandwidth_mode': bool,
+            'maximum_bandwidth': int,
             'respond_to_cq': bool,
             'tx_delay': int
         },
diff --git a/modem/data_frame_factory.py b/modem/data_frame_factory.py
index 2acc837c..cdd69362 100644
--- a/modem/data_frame_factory.py
+++ b/modem/data_frame_factory.py
@@ -98,6 +98,7 @@ class DataFrameFactory:
             "destination_crc": 3,
             "origin": 6,
             "session_id": 1,
+            "maximum_bandwidth": 2,
         }
 
         self.template_list[FR_TYPE.ARQ_SESSION_OPEN_ACK.value] = {
@@ -219,7 +220,7 @@ class DataFrameFactory:
 
             elif key in ["session_id", "speed_level", 
                             "frames_per_burst", "version",
-                            "offset", "total_length", "state", "type"]:
+                            "offset", "total_length", "state", "type", "maximum_bandwidth"]:
                 extracted_data[key] = int.from_bytes(data, 'big')
 
             elif key in ["snr"]:
@@ -328,11 +329,12 @@ class DataFrameFactory:
         test_frame[:1] = bytes([FR_TYPE.TEST_FRAME.value])
         return test_frame
 
-    def build_arq_session_open(self, destination, session_id):
+    def build_arq_session_open(self, destination, session_id, maximum_bandwidth):
         payload = {
             "destination_crc": helpers.get_crc_24(destination),
             "origin": helpers.callsign_to_bytes(self.myfullcall),
             "session_id": session_id.to_bytes(1, 'big'),
+            "maximum_bandwidth": maximum_bandwidth.to_bytes(2, 'big'),
         }
         return self.construct(FR_TYPE.ARQ_SESSION_OPEN, payload)
 
diff --git a/modem/explorer.py b/modem/explorer.py
index 994b76ea..dc11bcb3 100644
--- a/modem/explorer.py
+++ b/modem/explorer.py
@@ -33,7 +33,7 @@ class explorer():
         callsign = str(self.config['STATION']['mycall']) + "-" + str(self.config["STATION"]['myssid'])
         gridsquare = str(self.config['STATION']['mygrid'])
         version = str(self.modem_version)
-        bandwidth = str(self.config['MODEM']['enable_low_bandwidth_mode'])
+        bandwidth = str(self.config['MODEM']['maximum_bandwidth'])
         beacon = str(self.states.is_beacon_running)
         strength = str(self.states.s_meter_strength)
 
diff --git a/modem/frame_handler_cq.py b/modem/frame_handler_cq.py
index a23d2c69..9fc9ab4d 100644
--- a/modem/frame_handler_cq.py
+++ b/modem/frame_handler_cq.py
@@ -5,11 +5,22 @@ import frame_handler
 from message_system_db_messages import DatabaseManagerMessages
 
 
-class CQFrameHandler(frame_handler_ping.PingFrameHandler):
+class CQFrameHandler(frame_handler.FrameHandler):
 
-    def should_respond(self):
-        self.logger.debug(f"Respond to CQ: {self.config['MODEM']['respond_to_cq']}")
-        return self.config['MODEM']['respond_to_cq']
+    #def should_respond(self):
+    #    self.logger.debug(f"Respond to CQ: {self.config['MODEM']['respond_to_cq']}")
+    #    return bool(self.config['MODEM']['respond_to_cq'] and not self.states.getARQ())
+
+    def follow_protocol(self):
+        if self.states.getARQ():
+            return
+
+        self.logger.debug(
+            f"[Modem] Responding to request from [{self.details['frame']['origin']}]",
+            snr=self.details['snr'],
+        )
+
+        self.send_ack()
 
     def send_ack(self):
         factory = data_frame_factory.DataFrameFactory(self.config)
diff --git a/modem/frame_handler_ping.py b/modem/frame_handler_ping.py
index cf8f6499..c4d46c3b 100644
--- a/modem/frame_handler_ping.py
+++ b/modem/frame_handler_ping.py
@@ -15,15 +15,11 @@ class PingFrameHandler(frame_handler.FrameHandler):
     #        ft = self.details['frame']['frame_type']
     #        self.logger.info(f"[Modem] {ft} received but not for us.")
     #    return valid
-    
-    #def should_respond(self):
-    #    return self.is_frame_for_me()
 
     def follow_protocol(self):
-
-        if not self.should_respond():
+        if not bool(self.is_frame_for_me() and not self.states.getARQ()):
             return
-
+        
         self.logger.debug(
             f"[Modem] Responding to request from [{self.details['frame']['origin']}]",
             snr=self.details['snr'],
diff --git a/modem/server.py b/modem/server.py
index d2bd669d..dde5de07 100644
--- a/modem/server.py
+++ b/modem/server.py
@@ -33,7 +33,7 @@ from schedule_manager import ScheduleManager
 app = Flask(__name__)
 CORS(app, resources={r"/*": {"origins": "*"}})
 sock = Sock(app)
-MODEM_VERSION = "0.14.4-alpha"
+MODEM_VERSION = "0.14.5-alpha"
 
 # set config file to use
 def set_config():
diff --git a/tests/test_data_frame_factory.py b/tests/test_data_frame_factory.py
index 5f505662..f782f2e1 100755
--- a/tests/test_data_frame_factory.py
+++ b/tests/test_data_frame_factory.py
@@ -32,7 +32,7 @@ class TestDataFrameFactory(unittest.TestCase):
     def testARQConnect(self):
         dxcall = "DJ2LS-4"
         session_id = 123
-        frame = self.factory.build_arq_session_open(dxcall, session_id)
+        frame = self.factory.build_arq_session_open(dxcall, session_id, 1700)
         frame_data = self.factory.deconstruct(frame)
 
         self.assertEqual(frame_data['origin'], self.factory.myfullcall)