Tandy TRS‑80 Model 4P
The Model 4P (September 1983, Radio Shack catalog number 26-1080), is a self-contained luggable unit. It has all the features of the desktop Model 4 except for the ability to add two outboard floppy disk drives and the interface for cassette tape storage (audio sent to the cassette port in Model III mode goes to the internal speaker). It was sold with the two internal single-sided 180KB drives. Furthermore, it was later made with the Gate Array technology (catalog number 26-1080A). 80 Micro published an article describing a simple motherboard modification to enable the installation of two external floppy drives.
The 4P's video monitor is 9" in size, compared to the Model 4's 12". The smaller size, and sharper dots, produce better video output. The computer is compatible with popular internal Model 4 peripherals, and has a slot for an internal modem board. The Radio Shack modem uses its own proprietary command set and only supports communications at 300 baud. Teletrends produced a 1200 baud that uses the Hayes command set.
Tandy discontinued the 4P by early 1985, stating that "even though you won't find a more enthusiastic and devoted group of owners than our Model 4P folks, transportables just weren't moving well for any company that also sold a desktop version".