I envision the "parlor walls" as being similar to massive flat-screen TVs that run floor to ceiling and span multiple walls in a room. Montag and Mildred have three walls in one room that are now dedicated to these large screens, and Mildred wants a fourth to complete the room. However, the cost is so exorbitant that Montag tries to dissuade his wife from pushing the issue.
Mildred is so addicted to the programming on these walls that she considers the people who appear in the programming as her "family." In fact, when Montag asks her to turn off the screens for a while, she replies, "That's my family," feeling bound and connected to a false world. The parlor walls have replaced meaningful human interactions, and Mildred's suicidal tendencies reflect the innate harm in this loss of genuine human connection.
Bradbury's vision was quite impressive considering his setting. When writing this novel in the early 1950s, televisions were large box-like structures that took up a great deal of space. Programming was in largely black and white, and in 1950, only around twenty percent of homes owned a television. Yet the power of television was evident, and within a decade, around ninety percent of homes owned a television. Families gathered around a television to share programming together, and shows such as Fireside Theatre, I Love Lucy, and The Price Is Right became popular forms of entertainment.
While these large screens spanning the length and width of entire walls may not seem all that far-fetched to our modern and screen-dependent world, it was certainly far beyond the technologies which existed when Bradbury penned his novel. Bradbury nonetheless saw the power television exerted over the populace and realized the dangers inherent in spending increasing amounts of time in front of screens, a message that has become increasingly appropriate for modern societies.
In Bradbury's celebrated novel Fahrenheit 451, the parlor walls are massive television screens that take up entire living rooms and entertain shallow people like Mildred and her friends. These parlor walls produce bright, vivid images and are extremely loud and distracting. Montag has three parlor walls in his home, and Mildred insists that they purchase another to complete their viewing parlor. Mildred spends the vast majority of her leisure time glued to the parlor screens, consuming mindless entertainment. Mildred's favorite program on the parlor walls is a show she refers to as "the family," which lacks a plot and is simply a bunch of characters chatting to each other about nothing.
Similar to other programs on the parlor walls, "the family" is senseless entertainment meant to amuse unintelligent, superficial people like Mildred. Mildred is so addicted to watching television and consumed by the programs that she views the characters as her actual family. The parlor walls are also interactive, and Mildred is mailed parts of the script, which she reads aloud at different moments in the show.
The other shows Mildred watches are chaotic compilations of clips involving explosions, flying rockets, and violent altercations. In part 2, Montag interrupts Mildred and her friends while they are watching the parlor walls. In this scene, Bradbury depicts the sort of senseless entertainment on the television screens by writing,
Abruptly the room took off on a rocket flight into the clouds, it plunged into a lime-green sea where blue fish ate red and yellow fish. A minute later, Three White Cartoon Clowns chopped off each other's limbs to the accompaniment of immense incoming tides of laughter. Two minutes more and the room whipped out of town to the jet cars wildly circling an arena, bashing and backing up and bashing each other again.
The confusing, meaningless entertainment reflects the superficial culture of Bradbury's dystopia. Montag despises the parlor walls, and Mildred's addiction to television negatively affects her marriage.
Usually, the parlor walls contain wall-sized television screens. They get a screen that is as large as the wall in a room, and if they can get all four walls of a room covered in television screens, then you have a total and complete interactive and entertainment package. At the beginning of the novel, Mildred and Montag have three t.v. walls in their "parlor" or living room, and Mildred is hinting around to Montag that she wants yet another one. However, the cost for a t.v. wall is exhorbitant--it is nearly 1/3 of Montag's yearly salary, so it is a hard decision to make.
Mildred is addicted to watching television on these parlor walls. The programs that are on the television allow her to play an interactive role in the storyline, almost like a video game of sorts, where she is one of the characters in the drama. She spends most of her day watching and interacting with the television, and discusses all of the programs with her friends. It is a way for her to escape, and to not have to think about her life and how miserable she is. Montag jokes with her about the programs, calling the characters "the family," because she cares for them just like they are family members, and because she spends as much time with them as she does with him, if not more. So, the parlor walls are just large television screens that show programs. I hope that helps--good luck!