The filming of Scrubs takes place in Los Angeles, California in the North Hollywood Medical Center (a non-operational hospital). The fictional place that Sacred Heart is located in Scrubs is known as San DiFrangeles. Which happens to be a mixture of the name San Diego, San Francisco, and Los Angeles.
JTAG is an IEEE standard (1149.1) developed in the 1980s to solve electronic boards manufacturing issues. Nowadays it finds more use as programming, debug and probing port. But first, let's see JTAG's original use, boundary testing. Boundary testing
JTAG can take control (or hijack) the pins of all the ICs. On the picture, maybe JTAG is going to make all the CPU pins outputs, and all the FPGA pins inputs. Then by sending some data from the CPU pins, and reading the values from the FPGA pins, JTAG can make sure that the board connections are fine.