Patents

Mixing voice and data in the LAN goes back to at least this patent:

US 4,581,735 : Local area network packet protocol for combined voice and data transmission

INVENTORS: Lois E. Flamm and John O. Limb

ASSIGNEES AT&T Bell Laboratories, Murray Hill, NJ

ISSUED: Apr. 8 , 1986

FILED: May 31, 1983

ABSTRACT: In order to control the transfer of packets of information among a plurality of stations, the instant communications system, station and protocol contemplate first and second oppositely directed signal paths. At least two stations are coupled to both the first and the second signal paths. A station reads one signal from a path and writes another signal on the path. The one signal is read by an arrangement which electrically precedes the arrangement for writing the other signal. Packets are transmitted in a regular, cyclic sequence. A head station on a forward path writes a start cycle code for enabling each station to transmit one or more packets. If a station has a packet to transmit, it can read the bus field of a packet on the forward path.

https://www.google.com/patents/US4581735 Links to an external site.

Slide Notes

Before 1994, US patents normally lasted a maximum of 17 years.

Transcript

[slide50] Now, if we look into the patent literature, and it's useful learning how to read patents, we can find this patent by Lois Flamm and John Limb from Bell Laboratories, filed in 1983, which is entitled "Local area network packet protocol for combined voice and data transmission". So its a local area network for combined voice and data transmission. Why is it so interesting for us? Well, they already showed in 1983 that you could carry voice and data over the same land. There was no problem. How long do patents last? In this period of time, they lasted 17 years. That means all the patents for the basic technology have all past. So anyone can do this, there's no problem.