all abandoned.

The mall's communication cabinet is in the upper right corner, the other 3 blocks, rotating clockwise from the mall, are the central office's (CO) cross connection, an intermediate cabinet between the CO and the mall, and the CO itself. The diagram indicates that this cabinet multiplexes one DS3 circuit and 2 DS1 circuits over the fiber optic OC3 connection. The OC3 connection provides a maximum data rate of approximately 155Mbps, which then feeds the DS3 circuit, at a maximum speed of 44.7Mbps, and 2 DS1 circuits, each at a maximum of 1.544 Mbps. Of course, it's unlikely that the DS1 circuits were used for data, rather, each DS1 circuit can break out into 24 voice channels, providing the familiar old analog phone data limit of 64Kbps. Of course this was already woefully obsolete by the time I found it, considering that residential internet service often easy reaches 50Mbps. And as for bring 56 DS1 circuits, each able to serve 24 voice channels, that means they anticipated 1,344 new phone lines just for the 3rd wing of the mall. Talk about capacity planning.

Comments via Flickr