diff --git a/config_webrx.py b/config_webrx.py
index 4fc6eab..8d7f1e8 100644
--- a/config_webrx.py
+++ b/config_webrx.py
@@ -79,6 +79,8 @@ ppm = 0
 audio_compression="adpcm" #valid values: "adpcm", "none"
 fft_compression="adpcm" #valid values: "adpcm", "none"
 
+enable_digimodes=True #If set to True, it will take more CPU per client
+
 start_rtl_thread=True
 
 """
diff --git a/csdr.py b/csdr.py
index c1e4de1..477e55f 100755
--- a/csdr.py
+++ b/csdr.py
@@ -77,8 +77,8 @@ class dsp:
                 return fft_chain_base
         chain_begin=any_chain_base+"csdr shift_addition_cc --fifo {shift_pipe} | csdr fir_decimate_cc {decimation} {ddc_transition_bw} HAMMING | csdr bandpass_fir_fft_cc --fifo {bpf_pipe} {bpf_transition_bw} HAMMING | csdr squelch_and_smeter_cc --fifo {squelch_pipe} --outfifo {smeter_pipe} 5 1 | "
         if self.secondary_demodulator:
-            chain_begin+="tee {iqtee_pipe} | "
-            chain_begin+="tee {iqtee_pipe2} | "
+            chain_begin+="csdr tee {iqtee_pipe} | "
+            chain_begin+="csdr tee {iqtee2_pipe} | "
         chain_end = ""
         if self.audio_compression=="adpcm":
             chain_end = " | csdr encode_ima_adpcm_i16_u8"
@@ -90,16 +90,12 @@ class dsp:
         secondary_chain_base="cat {input_pipe} | "
 
         if which == "fft":
-            return secondary_chain_base+"csdr fft_cc {secondary_fft_size} {secondary_fft_block_size} | csdrr logpower_cf -70 | csdr fft_one_side_ff {secondary_fft_size}"
+            return secondary_chain_base+"csdr realpart_cf | csdr fft_fc {secondary_fft_size} {secondary_fft_block_size} | csdr logpower_cf -70 | csdr fft_one_side_ff {secondary_fft_size}" + (" | csdr compress_fft_adpcm_f_u8 {secondary_fft_size}" if self.fft_compression=="adpcm" else "")
         elif which == "bpsk31":
-            return secondary_chain_base+"""csdr dsb_fc | \
-csdr shift_addition_cc {secondary_shift_pipe} | \
-csdr REM fir_decimate_cc {secondary_decimation} | \
+            return secondary_chain_base+"""csdr shift_addition_cc {secondary_shift_pipe} | \
 csdr bandpass_fir_fft_cc -{secondary_bpf_cutoff} {secondary_bpf_cutoff} {secondary_bpf_transition_bw} HAMMING | \
 csdr simple_agc_cc 0.0001 0.5 | \
-csdr matched_filter_cc COSINE 48 | \
 csdr timing_recovery_cc EARLYLATE {secondary_samples_per_bits} --add_q | \
-
 CSDR_FIXED_BUFSIZE=1 csdr realpart_cf | \
 CSDR_FIXED_BUFSIZE=1 csdr binary_slicer_f_u8 | \
 CSDR_FIXED_BUFSIZE=1 csdr differential_decoder_u8_u8 | \
@@ -112,37 +108,44 @@ CSDR_FIXED_BUFSIZE=1 csdr psk31_varicode_decoder_u8_u8
     def secondary_fft_block_size(self):
         return (self.samp_rate/self.decimation)/self.fft_fps
 
-    def secondary_decimation(self, which):
-        return 1
+    def secondary_decimation(self):
+        return 1 #currently unused
 
-    def secondary_bpf_cutoff(self, which):
+    def secondary_bpf_cutoff(self):
         if self.secondary_demodulator == "bpsk31":
-             return 31.25 / self.if_samp_rate()
+             return (31.25/2) / self.if_samp_rate()
         return 0
 
-    def secondary_bpf_transition_bw(self, which):
+    def secondary_bpf_transition_bw(self):
         if self.secondary_demodulator == "bpsk31":
-            return (31.25 / 2) * self.if_samp_rate()
+            return (31.25/2) / self.if_samp_rate()
+        return 0
+
+    def secondary_samples_per_bits(self):
+        if self.secondary_demodulator == "bpsk31":
+            return int(round(self.if_samp_rate()/31.25))
         return 0
 
     def start_secondary_demodulator(self):
         if(not self.secondary_demodulator): return
-        secondary_command_fft=secondary_chain("fft")
+        print "[openwebrx] starting secondary demodulator from IF input sampled at %d"%self.if_samp_rate()
+        secondary_command_fft=self.secondary_chain("fft")
+        secondary_command_demod=self.secondary_chain(self.secondary_demodulator)
+        self.try_create_pipes(self.secondary_pipe_names, secondary_command_demod + secondary_command_fft)
+
         secondary_command_fft=secondary_command_fft.format( \
             input_pipe=self.iqtee_pipe, \
             secondary_fft_size=self.secondary_fft_size, \
             secondary_fft_block_size=self.secondary_fft_block_size(), \
             )
-        secondary_command_demod=self.secondary_chain(self.secondary_demodulator)
-        secondary_command_demod.format( \
+        secondary_command_demod=secondary_command_demod.format( \
             input_pipe=self.iqtee2_pipe, \
             secondary_shift_pipe=self.secondary_shift_pipe, \
-            secondary_decimation=self.secondary_decimation(self.secondary_demodulator), \
-            secondary_samples_per_bits=self.secondary_samples_per_bits(self.secondary_demodulator), \
-            secondary_bpf_cutoff=self.secondary_bpf_cutoff(self.secondary_demodulator), \
-            secondary_bpf_transition_bw=self.secondary_bpf_transition_bw(self.secondary_demodulator)
+            secondary_decimation=self.secondary_decimation(), \
+            secondary_samples_per_bits=self.secondary_samples_per_bits(), \
+            secondary_bpf_cutoff=self.secondary_bpf_cutoff(), \
+            secondary_bpf_transition_bw=self.secondary_bpf_transition_bw()
             )
-        try_create_pipes(secondary_command_demod + secondary_command_fft, self.secondary_pipe_names)
 
         print "[openwebrx-dsp-plugin:csdr] secondary command (fft) =", secondary_command_fft
         print "[openwebrx-dsp-plugin:csdr] secondary command (demod) =", secondary_command_demod
@@ -151,7 +154,9 @@ CSDR_FIXED_BUFSIZE=1 csdr psk31_varicode_decoder_u8_u8
         #if self.csdr_dynamic_bufsize: my_env["CSDR_DYNAMIC_BUFSIZE_ON"]="1";
         if self.csdr_print_bufsizes: my_env["CSDR_PRINT_BUFSIZES"]="1";
         self.secondary_process_fft = subprocess.Popen(secondary_command_fft, stdout=subprocess.PIPE, shell=True, preexec_fn=os.setpgrp, env=my_env)
+        print "[openwebrx-dsp-plugin:csdr] Popen on secondary command (fft)"
         self.secondary_process_demod = subprocess.Popen(secondary_command_demod, stdout=subprocess.PIPE, shell=True, preexec_fn=os.setpgrp, env=my_env)
+        print "[openwebrx-dsp-plugin:csdr] Popen on secondary command (demod)"
         self.secondary_processes_running = True
 
         #open control pipes for csdr and send initialization data
@@ -159,6 +164,9 @@ CSDR_FIXED_BUFSIZE=1 csdr psk31_varicode_decoder_u8_u8
             self.secondary_shift_pipe_file=open(self.secondary_shift_pipe,"w")
             self.set_secondary_offset_freq(self.secondary_offset_freq)
 
+        self.set_pipe_nonblocking(self.secondary_process_demod.stdout)
+        self.set_pipe_nonblocking(self.secondary_process_fft.stdout)
+
     def set_secondary_offset_freq(self, value):
         self.secondary_offset_freq=value
         if self.secondary_processes_running:
@@ -178,6 +186,9 @@ CSDR_FIXED_BUFSIZE=1 csdr psk31_varicode_decoder_u8_u8
     def read_secondary_fft(self, size):
         return self.secondary_process_fft.stdout.read(size)
 
+    def get_secondary_demodulator(self):
+        return self.secondary_demodulator
+
     def set_audio_compression(self,what):
         self.audio_compression = what
 
@@ -188,6 +199,10 @@ CSDR_FIXED_BUFSIZE=1 csdr psk31_varicode_decoder_u8_u8
         if self.fft_compression=="none": return self.fft_size*4
         if self.fft_compression=="adpcm": return (self.fft_size/2)+(10/2)
 
+    def get_secondary_fft_bytes_to_read(self):
+        if self.fft_compression=="none": return self.secondary_fft_size*4
+        if self.fft_compression=="adpcm": return (self.secondary_fft_size/2)+(10/2)
+
     def set_samp_rate(self,samp_rate):
         #to change this, restart is required
         self.samp_rate=samp_rate
@@ -273,7 +288,9 @@ CSDR_FIXED_BUFSIZE=1 csdr psk31_varicode_decoder_u8_u8
         return self.ddc_transition_bw_rate*(self.if_samp_rate()/float(self.samp_rate))
 
     def try_create_pipes(self, pipe_names, command_base):
+        print "try_create_pipes"
         for pipe_name in pipe_names:
+            print "\t"+pipe_name
             if "{"+pipe_name+"}" in command_base:
                 setattr(self, pipe_name, self.pipe_base_path+pipe_name)
                 self.mkfifo(getattr(self, pipe_name))
@@ -287,6 +304,9 @@ CSDR_FIXED_BUFSIZE=1 csdr psk31_varicode_decoder_u8_u8
                 try: os.unlink(pipe_path)
                 except: print "[openwebrx-dsp-plugin:csdr] try_delete_pipes() :: unlink failed: " + pipe_path
 
+    def set_pipe_nonblocking(self, pipe):
+        flags = fcntl.fcntl(pipe, fcntl.F_GETFL)
+        fcntl.fcntl(pipe, fcntl.F_SETFL, flags | os.O_NONBLOCK)
 
     def start(self):
         command_base=self.chain(self.demodulator)
@@ -321,7 +341,7 @@ CSDR_FIXED_BUFSIZE=1 csdr psk31_varicode_decoder_u8_u8
             last_decimation=self.last_decimation, fft_size=self.fft_size, fft_block_size=self.fft_block_size(), fft_averages=self.fft_averages, \
             bpf_transition_bw=float(self.bpf_transition_bw)/self.if_samp_rate(), ddc_transition_bw=self.ddc_transition_bw(), \
             flowcontrol=int(self.samp_rate*2), start_bufsize=self.base_bufsize*self.decimation, nc_port=self.nc_port, \
-            squelch_pipe=self.squelch_pipe, smeter_pipe=self.smeter_pipe )
+            squelch_pipe=self.squelch_pipe, smeter_pipe=self.smeter_pipe, iqtee_pipe=self.iqtee_pipe, iqtee2_pipe=self.iqtee2_pipe )
 
         print "[openwebrx-dsp-plugin:csdr] Command =",command
         #code.interact(local=locals())
@@ -343,7 +363,7 @@ CSDR_FIXED_BUFSIZE=1 csdr psk31_varicode_decoder_u8_u8
             self.set_squelch_level(self.squelch_level)
         if self.smeter_pipe != None:
             self.smeter_pipe_file=open(self.smeter_pipe,"r")
-            fcntl.fcntl(self.smeter_pipe_file, fcntl.F_SETFL, os.O_NONBLOCK)
+            self.set_pipe_nonblocking(self.smeter_pipe_file)
 
         self.start_secondary_demodulator()
 
diff --git a/htdocs/index.wrx b/htdocs/index.wrx
index 12b1314..1d92b38 100644
--- a/htdocs/index.wrx
+++ b/htdocs/index.wrx
@@ -34,6 +34,7 @@
             var waterfall_min_level_default=%[WATERFALL_MIN_LEVEL];
             var waterfall_max_level_default=%[WATERFALL_MAX_LEVEL];
             var waterfall_auto_level_margin=%[WATERFALL_AUTO_LEVEL_MARGIN];
+            var server_enable_digimodes=%[ENABLE_DIGIMODES];
         </script>
         <script src="sdr.js"></script>
         <script src="openwebrx.js"></script>
@@ -130,7 +131,7 @@
                         </div>
                     </div>
                 </div>
-                <div class="openwebrx-panel" id="openwebrx-panel-log" data-panel-name="debug" data-panel-pos="left" data-panel-order="1" data-panel-size="619,142">
+                <div class="openwebrx-panel" id="openwebrx-panel-log" data-panel-name="debug" data-panel-pos="left" data-panel-order="1" data-panel-size="619,137">
                     <div class="openwebrx-panel-inner nano" id="openwebrx-log-scroll">
                         <div class="nano-content">
                             <div id="openwebrx-client-log-title">OpenWebRX client log</strong><span id="openwebrx-problems"></span></div>
diff --git a/htdocs/openwebrx.js b/htdocs/openwebrx.js
index bd88055..1075ba3 100644
--- a/htdocs/openwebrx.js
+++ b/htdocs/openwebrx.js
@@ -1165,10 +1165,15 @@ function on_ws_recv(evt)
 			var waterfall_i16=fft_codec.decode(new Uint8Array(evt.data,4));
 			var waterfall_f32=new Float32Array(waterfall_i16.length-COMPRESS_FFT_PAD_N);
 			for(var i=0;i<waterfall_i16.length;i++) waterfall_f32[i]=waterfall_i16[i+COMPRESS_FFT_PAD_N]/100;
-            if(evt.data[3]=="S") secondary_demod_waterfall_add_queue(waterfall_f32);
+            if(evt.data[3]=="S") secondary_demod_waterfall_add_queue(waterfall_f32), console.log("FFTS");
             else waterfall_add_queue(waterfall_f32);
 		}
-	} else if(firstChars=="MSG")
+	} 
+    else if(firstChars=="DAT")
+    {
+        console.log("DAT");
+	} 
+    else if(firstChars=="MSG")
 	{
 		/*try
 		{*/
diff --git a/openwebrx.py b/openwebrx.py
index d6e5ba8..59d6d5d 100755
--- a/openwebrx.py
+++ b/openwebrx.py
@@ -92,7 +92,8 @@ def handle_signal(sig, frame):
             print
             for key in client._fields:
                 print "\t%s = %s"%(key,str(getattr(client,key)))
-
+    elif sig == signal.SIGUSR2:
+        code.interact(local=globals())
     else:
         print "[openwebrx] Ctrl+C: aborting."
         cleanup_clients(True)
@@ -128,6 +129,7 @@ def main():
     #Set signal handler
     signal.signal(signal.SIGINT, handle_signal) #http://stackoverflow.com/questions/1112343/how-do-i-capture-sigint-in-python
     signal.signal(signal.SIGUSR1, handle_signal)
+    signal.signal(signal.SIGUSR2, handle_signal)
 
     #Pypy
     if pypy: print "pypy detected (and now something completely different: c code is expected to run at a speed of 3*10^8 m/s?)"
@@ -460,6 +462,7 @@ class WebRXHandler(BaseHTTPRequestHandler):
                     dsp=csdr.dsp()
                     dsp_initialized=False
                     dsp.set_audio_compression(cfg.audio_compression)
+                    dsp.set_fft_compression(cfg.fft_compression) #used by secondary chains
                     dsp.set_format_conversion(cfg.format_conversion)
                     dsp.set_offset_freq(0)
                     dsp.set_bpf(-4000,4000)
@@ -470,6 +473,7 @@ class WebRXHandler(BaseHTTPRequestHandler):
                     access_log("Started streaming to client: "+self.client_address[0]+"#"+myclient.id+" (users now: "+str(len(clients))+")")
 
                     myclient.loopstat=0
+                    do_secondary_demod=False
 
                     while True:
                         if myclient.closed[0]:
@@ -512,6 +516,17 @@ class WebRXHandler(BaseHTTPRequestHandler):
                             rxws.send(self,myclient.bcastmsg)
                             myclient.bcastmsg=""
 
+                        # ========= send secondary =========
+                        if do_secondary_demod:
+                            while True:
+                                secondary_spectrum_data=dsp.read_secondary_fft(dsp.get_secondary_fft_bytes_to_read())
+                                if not secondary_spectrum_data: break
+                                rxws.send(self, "FFTS", secondary_spectrum_data)
+                            while True:
+                                secondary_demod_data=dsp.read_secondary_demod(1)
+                                if not secondary_demod_data: break
+                                rxws.send(self, "DAT ", secondary_demod_data)
+
                         # ========= process commands =========
                         while True:
                             myclient.loopstat=50
@@ -526,13 +541,13 @@ class WebRXHandler(BaseHTTPRequestHandler):
                                 filter_limit=dsp.get_output_rate()/2
                                 for pair in pairs:
                                     param_name, param_value = pair.split("=")
-                                    if param_name == "low_cut" and -filter_limit <= float(param_value) <= filter_limit:
+                                    if param_name == "low_cut" and -filter_limit <= int(param_value) <= filter_limit:
                                         bpf_set=True
                                         new_bpf[0]=int(param_value)
-                                    elif param_name == "high_cut" and -filter_limit <= float(param_value) <= filter_limit:
+                                    elif param_name == "high_cut" and -filter_limit <= int(param_value) <= filter_limit:
                                         bpf_set=True
                                         new_bpf[1]=int(param_value)
-                                    elif param_name == "offset_freq" and -cfg.samp_rate/2 <= float(param_value) <= cfg.samp_rate/2:
+                                    elif param_name == "offset_freq" and -cfg.samp_rate/2 <= int(param_value) <= cfg.samp_rate/2:
                                         myclient.loopstat=510
                                         dsp.set_offset_freq(int(param_value))
                                     elif param_name == "squelch_level" and float(param_value) >= 0:
@@ -555,6 +570,18 @@ class WebRXHandler(BaseHTTPRequestHandler):
                                             myclient.loopstat=550
                                             dsp.start()
                                             dsp_initialized=True
+                                    elif param_name=="secondary_mod" and cfg.enable_digimodes:
+                                        if (dsp.get_secondary_demodulator() != param_value):
+                                            if dsp_initialized: dsp.stop()
+                                            if param_value == "off":
+                                                dsp.set_secondary_demodulator(None)
+                                                do_secondary_demod = False
+                                            else:
+                                                dsp.set_secondary_demodulator(param_value)
+                                                do_secondary_demod = True
+                                            if dsp_initialized: dsp.start()
+                                    elif param_name=="secondary_offset_freq" and 0 <= int(param_value) <= dsp.if_samp_rate()/2 and cfg.enable_digimodes:
+                                        dsp.set_secondary_offset_freq(int(param_value))
                                     else:
                                         print "[openwebrx-httpd:ws] invalid parameter"
                                 if bpf_set:
@@ -642,7 +669,8 @@ class WebRXHandler(BaseHTTPRequestHandler):
                         ("%[WATERFALL_COLORS]",cfg.waterfall_colors),
                         ("%[WATERFALL_MIN_LEVEL]",str(cfg.waterfall_min_level)),
                         ("%[WATERFALL_MAX_LEVEL]",str(cfg.waterfall_max_level)),
-                        ("%[WATERFALL_AUTO_LEVEL_MARGIN]","[%d,%d]"%cfg.waterfall_auto_level_margin)
+                        ("%[WATERFALL_AUTO_LEVEL_MARGIN]","[%d,%d]"%cfg.waterfall_auto_level_margin),
+                        ("%[ENABLE_DIGIMODES]",("true" if cfg.enable_digimodes else "false"))
                     )
                     for rule in replace_dictionary:
                         while data.find(rule[0])!=-1: