there are some GSM sample files listed on wiki : http://wiki.wireshark.org/SampleCaptures#head-9bb933141650a94e823bbb9dfacb304445b0cde2 but they are not empty, am I missing anything? http://wiki.wireshark.org/SampleCaptures?action=AttachFile&do=view&target=abis-network-accept.pcap http://wiki.wireshark.org/SampleCaptures?action=AttachFile&do=view&target=abis-network-reject.pcap -- FIXME if it is wrong.