Near the end of the TRS-80 product run came the Tandy TRS-80 Model 4 from Tandy / Radio Shack. Introduced in 1983, it was an upgrade from the Model 3 in that it ran at a blazing 4 MHz using a Zilog Z80 processor and had a display of 80 columns by 24 lines. The Model 3, by comparison, only ran at 2 MHz and displayed 64 columns and 16 lines. For those who longed for the Model 3 performance the Model for did have a Model 3 emulation mode in which it could run at Model 3 performance levels. Model 3 owners also had an upgrade kit kit available to them and could convert their Model 3 in to a Model 4.
The Model 4 originally retailed at around $1999.00 but the price was later dropped to around $999.00 and seven years after its introduction it was being blown out at around $600.00.
The TRS-80 Model 4 came with either 64k or 128k ram and had either one or two 5.25″ floppy drives of 184 KB each. A later Model 4D, or DeskMate, had double sided 384 KB drives. A graphics adapter that came with BASICG was also available for the Model 4.
The earliest versions of the TRS-80 Model 4 had a black and white display which later changed to green. Also, the early run of the Model 4 had a non-gate array which was changed to a gate array in later production. You can tell the ealry versions from the laters one’s by the keyboard layout. The early version had the up/down and left/right keys on opposite sides of the keyboard. The later version clustered the arrow keys together on the right side.
Tandy also produced a Model 4P which was a “transportable” computer and had a smaller display, detached keyboard, space for an internal modem and sold for $1799.00.
Many many current computer professionals grew up using a TRS-80 Model 4. Hours spent playing games such as Zaxxon, Frogger and Computer Diplomacy along with programming in BASIC led to lucrative future careers in the computing fields. For that reason the TRS-80 Model 4 is very collectible as many want to relive their younger days and enjoyable times on the Model 4. Quite a few of these machines were made so they are not that hard to find. In really good working condition they can be found for $150.00 to $300.00. For more info on the TRS-80 Model 4 and other TRS-80 models check the TRS-80.com site.