Hemodiealysis (225.n.2)

COMMUNICATION Cellular technology is based on a number of essential elements, which enable cell phones (with a unique SIM card) to talk to the cell stations (towers) for a particular carrier. When the cell phone initially connects to the network, it finds and hand-shakes with a nearby tower.

As the phone moves around, it gets transferred to a new tower so the connection is never dropped. Given distance and speed can vary for each phone, this transfer protocol is both somewhat complicated and mathematically beautiful. But the important part is simply each phone has a unique ID that a carrier’s network recognizes, connects with, and bills the account for.

We have a couple hundred different SIM cards in our team’s cellular phones and cell-based internet routers. Each of these SIM cards have a unique ID (IMSI), and the software in the phone or modem does the connection to an appropriate tower near the Boardwalk compound.

Unfortunately for us, the stations are computers and carriers can use them to both identify what phone is connecting to what tower, and to disable that connection. Given our phones were all physically stationed at Boardwalk, there would only be a half-dozen plausible towers per network they had to monitor. We appear to be very bad at hide-andgo-seek.

Our phones started disconnecting at Noon on Wednesday. They kept mine open just to tease (or maybe respect) me, which made me doubt whether Amasa and Dr. A. knew what was going on. Although not all the cellular modems were online, we expected maybe a few hours at best when they came up. We had a couple days of communication before we were completely blacked out.

Communication is essential which is why we had at least two solutions to this blackout problem. The less reliable but more communicative solution was C1 and C20. These two containers contained three important things: (1) cellular antennas, (2) computers, and (3) a large bank of SIM cards. I stole this idea from companies in China and elsewhere that provide virtual SIMs to people who would prefer to pay local vs. international cell-phone rates. As in… pretty much everyone except Larry and Elon.

Each of the containers had a bank of a thousand SIM cards, which the computers could use with the antennas to talk to cell towers up to 45 miles away (as the crow flies). This blanketed the Bay Area, and - 84 -