It was around 2008 and I just landed my first full time networking job. Prior to my arrival, the company had replaced their analog phone system with a 100% VoIP solution using Shoretel. They were experiencing a lot of call issues between the main office and a call center that was about 1/2 mile away. They had a redundant network set up where the primary link was a line of sight radio connection with a T1 as a backup. The primary line of sight radio was an antenna mounted on the top of the main office that shot to an antenna on top of a 20+ story building downtown. In what we called "the turret", there was a small 8 port switch that connected to a second antenna that shot down to the building where the call center was located. I spent weeks working with Shoretel and Proxim (radio vendor). We replaced antennas, combed through the phone system looking for configuration issues, and even replaced that small 8 port switch, but nothing resolved the packet loss and voice quality issues. Finally, I read the data sheet for the Proxim radio and found that it used "Time Division Duplex". For you kids out there, this is where for one period of time, the radio will send and for another period of time it will received, but it will never send and receive at the same time. It's amazing what you learn if you just RTFM. 🙂
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