diff --git a/pySim-trace.py b/pySim-trace.py
index 79069a6..bb1805c 100755
--- a/pySim-trace.py
+++ b/pySim-trace.py
@@ -114,36 +114,45 @@
             #print(inst)
             self.format_capdu(inst)
 
-option_parser = argparse.ArgumentParser(prog='pySim-trace', description='Osmocom pySim high-level SIM card trace decoder',
+option_parser = argparse.ArgumentParser(description='Osmocom pySim high-level SIM card trace decoder',
                                         formatter_class=argparse.ArgumentDefaultsHelpFormatter)
 
 global_group = option_parser.add_argument_group('General Options')
 global_group.add_argument('--no-suppress-select', action='store_false', dest='suppress_select',
-                          help="Don't suppress displaying SELECT APDUs")
+                          help="""
+    Don't suppress displaying SELECT APDUs. We normally suppress them as they just clutter up
+    the output without giving any useful information.  Any subsequent READ/UPDATE/... operations
+    on the selected file will log the file name most recently SELECTed.""")
 global_group.add_argument('--no-suppress-status', action='store_false', dest='suppress_status',
-                          help="Don't suppress displaying STATUS APDUs")
+                          help="""
+    Don't suppress displaying STATUS APDUs. We normally suppress them as they don't provide any
+    information that was not already received in resposne to the most recent SEELCT.""")
 
 subparsers = option_parser.add_subparsers(help='APDU Source', dest='source', required=True)
 
-parser_gsmtap = subparsers.add_parser('gsmtap-udp', help='Live capture of GSMTAP-SIM on UDP port')
+parser_gsmtap = subparsers.add_parser('gsmtap-udp', help="""
+    Read APDUs from live capture by receiving GSMTAP-SIM packets on specified UDP port.
+    Use this for live capture from SIMtrace2 or osmo-qcdiag.""")
 parser_gsmtap.add_argument('-i', '--bind-ip', default='127.0.0.1',
                            help='Local IP address to which to bind the UDP port')
 parser_gsmtap.add_argument('-p', '--bind-port', default=4729,
                            help='Local UDP port')
 
 parser_gsmtap_pyshark_pcap = subparsers.add_parser('gsmtap-pyshark-pcap', help="""
-    PCAP file containing GSMTAP (SIM APDU) communication; processed via pyshark.""")
+    Read APDUs from PCAP file containing GSMTAP (SIM APDU) communication; processed via pyshark.
+    Use this if you have recorded a PCAP file containing GSMTAP (SIM APDU) e.g. via tcpdump or
+    wireshark/tshark.""")
 parser_gsmtap_pyshark_pcap.add_argument('-f', '--pcap-file', required=True,
                                        help='Name of the PCAP[ng] file to be read')
 
 parser_rspro_pyshark_pcap = subparsers.add_parser('rspro-pyshark-pcap', help="""
-    PCAP file containing RSPRO (osmo-remsim) communication; processed via pyshark.
+    Read APDUs from PCAP file containing RSPRO (osmo-remsim) communication; processed via pyshark.
     REQUIRES OSMOCOM PATCHED WIRESHARK!""")
 parser_rspro_pyshark_pcap.add_argument('-f', '--pcap-file', required=True,
                                        help='Name of the PCAP[ng] file to be read')
 
 parser_rspro_pyshark_live = subparsers.add_parser('rspro-pyshark-live', help="""
-    Live capture of RSPRO (osmo-remsim) communication; processed via pyshark.
+    Read APDUs from live capture of RSPRO (osmo-remsim) communication; processed via pyshark.
     REQUIRES OSMOCOM PATCHED WIRESHARK!""")
 parser_rspro_pyshark_live.add_argument('-i', '--interface', required=True,
                                        help='Name of the network interface to capture on')