diff --git a/dmrlink.py b/dmrlink.py
index 00b6854..6467a02 100755
--- a/dmrlink.py
+++ b/dmrlink.py
@@ -949,6 +949,7 @@ class IPSC(DatagramProtocol):
     def datagramReceived(self, data, (host, port)):
         _packettype = data[0:1]
         _peerid     = data[1:5]
+        _ipsc_seq   = data[5:6]
         
         # AUTHENTICATE THE PACKET
         if not self.validate_auth(self._local['AUTH_KEY'], data):
@@ -966,12 +967,25 @@ class IPSC(DatagramProtocol):
                 
             # ORIGINATED BY SUBSCRIBER UNITS - a.k.a someone transmitted
             if _packettype in USER_PACKETS:
-                # Extract commonly used items from the packet header
+                # Extract IPSC header not already extracted
                 _src_sub    = data[6:9]
                 _dst_sub    = data[9:12]
-                _call       = int_id(data[17:18])
-                _ts         = bool(_call & TS_CALL_MSK)
-                _end        = bool(_call & END_MSK)
+                _call_type  = data[12:13]
+                _unknown_1  = data[13:17]
+                _call_info  = int_id(data[17:18])                
+                _ts         = bool(_call_info & TS_CALL_MSK)
+                _end        = bool(_call_info & END_MSK)
+                
+                # Extract RTP header fields
+                '''
+                Coming soon kids!!!
+                Looks like version, padding, extention, CSIC, payload type and SSID never change.
+                The things we might care about are below.
+                _rtp_byte_1 = int_id(data[18:19])
+                _rtp_byte_2 = int_id(data[19:20])
+                _rtp_seq    = int_id(data[20:22])
+                _rtp_tmstmp = int_id(data[22:26])
+                '''
 
                 # User Voice and Data Call Types:
                 if _packettype == GROUP_VOICE:
diff --git a/ipsc/ipsc_mask.py b/ipsc/ipsc_mask.py
index 431cf7d..6c160e6 100644
--- a/ipsc/ipsc_mask.py
+++ b/ipsc/ipsc_mask.py
@@ -6,6 +6,11 @@
 # Creative Commons, 444 Castro Street, Suite 900, Mountain View,
 # California, 94041, USA.
 
+# MASKS FOR IPSC, RTP AND THE RTP PAYLOAD (DMR FRAME + FRIENDS) ARE LOCATED
+# IN THIS FILE IN THIS ORDER: IPSC, RTP, PAYLOAD
+
+# IPSC MASK VALUES
+#
 # LINKING STATUS:
 #	Byte 1 - BIT FLAGS:
 #	      xx.. .... = Peer Operational (01 only known valid value)
@@ -53,11 +58,33 @@ VOICE_CALL_MSK     = 0b00000100
 MSTR_PEER_MSK      = 0b00000001
 
 # TIMESLOT CALL & STATUS BYTE
-
 #   Byte 17 of Group and Private Voice/Data Packets
 #       ..x.. ....TS Value (0=TS1, 1=TS2)
 #       .x... ....TS In Progress/End (0=In Progress, 1=End)
 #       Possible values: 0x00=TS1, 0x20=TS2, 0x40=TS1 End, 0x60=TS2 End
 #   MASK VALUE:
 END_MSK             = 0b01000000
-TS_CALL_MSK         = 0b00100000
\ No newline at end of file
+TS_CALL_MSK         = 0b00100000
+
+
+
+# RTP MASK VALUES
+# Bytes 1 and 2 of the RTP header are bit-fields, the rest
+# are at least one byte long, and do not need masked
+#   Byte 1
+RTP_VER_MSK         = 0b11000000
+RTP_PAD_MSK         = 0b00100000
+RTP_EXT_MSK         = 0b00010000
+RTP_CSIC_MSK        = 0b00001111
+#   Byte 2
+RTP_MRKR_MSK        = 0b10000000
+RTP_PAY_TYPE_MSK    = 0b01111111
+
+
+
+# RTP PAYLOAD (DMR FRAME + FRIENDS) MASK VALUES
+# This one is tricky. The DMR Frame contents are here
+# and re-ordered from their position in the original DMR
+# frame format. There are also some other friends in here
+# that Motorla added.
+# 
\ No newline at end of file