The cerebral impulse relay machine, called C.I.R. or "sir", is a special research project at Madacorp headed by Julian Ballantine. Madacorp caused Stephen Trager to lose his job to be hired to run the software for CIR. It seems to work similarly to an MRI for only the brain, and Ballantine tells Kyle that CIR is like a giant magnet. Although the public explanation is that it could be used to study and heal diseases, it allows direct communication with a person's brain to manipulate the mind. What we see of it is Ballantine's attempts to "extract" information that 781227 had taken from Zzyzx.
The first use is to implant a personality and history into 781228, to make her think she is Jessi Hollander, sister of Emily Hollander who is assigned to the case. It seems to go alright, until Jessi begins acting "like any other teenage girl." Ballantine says "She's a computer with a glitch. Bring her in, we'll fix it." But Jessi keeps recalling memories that the CIR was supposed to have erased, and she keeps developing a personality that is not Emily's sister.
When Lori ruins the plan to take Ballantine's ring, and Tom Foss is captured, Ballantine has Tom strapped into the machine to test its power against a "mental firewall". Tom strains so hard to resist its invasion of his memories and his mind, that the monitoring devices warn of cardiac arrest. Ballantine sees that there was no damage to Tom's mental functions, and is confident that it will work with Kyle too.
After Jessi takes the information from Kyle, as she was programmed to do, it is torturing her mind so that she can hardly wait to get in the chair to be rid of it. But Kyle manages to connect with her subconsciously to let the data transfer back to him.
Kyle is then put into the chair, as he has planned. He tries so hard to resist, that CIR begins to erase his life memories. When Jessi enters his mind to help him, together they create an energy surge through CIR that blows out Madacorp's entire computer system and causes a city-wide blackout.
We see no more of the chair, or of Ballantine.