A method comprising: detecting, by a supervisory network Monitor, a transmission of a data packet from a first device to at least one second device over a supervisory network, wherein the supervisory network Monitor is neither a source or destination of the data packet, and wherein the first device and the at least one second device are directly connected through the supervisory network; obtaining, by the supervisory network Monitor, a copy of the transmitted data packet; decoding and storing, by the supervisory network Monitor, the obtained data packet, the step of decoding comprising: classifying the obtained data packet as a single-packet message, or as part of a multi-packet message; if classified as a single-packet message the obtained data packet is immediately decoded and recorded onto a mass storage device; and if classified as part of a multi-packet message, the obtained data packet is saved, once the supervisory network Monitor obtains one or more other data packets of the multi-packet message, the obtained data packets are assembled into a full message, the full message is then decoded into human-readable form and recorded on the mass storage device; and detecting, by the supervisory network Monitor, one or more errors in or associated with the obtained data packet(s) including detecting any packet sequence number errors, orphan packets, or timed-out message reconstructions. detecting, by a supervisory network Monitor, a transmission of a data packet from a first device to at least one second device over a supervisory network, wherein the supervisory network Monitor is neither a source or destination of the data packet, and wherein the first device and the at least one second device are directly connected through the supervisory network; obtaining, by the supervisory network Monitor, a copy of the transmitted data packet; decoding and storing, by the supervisory network Monitor, the obtained data packet, the step of decoding comprising: classifying the obtained data packet as a single-packet message, or as part of a multi-packet message; if classified as a single-packet message the obtained data packet is immediately decoded and recorded onto a mass storage device; and if classified as part of a multi-packet message, the obtained data packet is saved, once the supervisory network Monitor obtains one or more other data packets of the multi-packet message, the obtained data packets are assembled into a full message, the full message is then decoded into human-readable form and recorded on the mass storage device; and classifying the obtained data packet as a single-packet message, or as part of a multi-packet message; if classified as a single-packet message the obtained data packet is immediately decoded and recorded onto a mass storage device; and if classified as part of a multi-packet message, the obtained data packet is saved, once the supervisory network Monitor obtains one or more other data packets of the multi-packet message, the obtained data packets are assembled into a full message, the full message is then decoded into human-readable form and recorded on the mass storage device; and detecting, by the supervisory network Monitor, one or more errors in or associated with the obtained data packet(s) including detecting any packet sequence number errors, orphan packets, or timed-out message reconstructions.