Articles in the "Hardware" Category

TRS-80 Digitizer

The TRS-80 Digitizer (catalog number 26-1195), available in November 1981, provided a way to digitize maps, blueprints, and charts in an era before document scanners were affordable or commonly available. The Digitizer, which measured 2¼″ by 15½″ by 4¼″, cost $449.00 and connected to the TRS-80 Model I or Color Computer through the cassette port or to other TRS-80 models through the RS-232 port. (Oddly, the Model III couldn’t be connected through the cassette port like the Model I.)

The manual described the concept behind the TRS-80 Digitizer:

What exactly is a digitizer? Basically, it’s a device that describes a specific point on a sheet of paper in terms of its X-Y (Cartesian) coordinates. For example, if you didn’t have a Digitizer and you wanted to describe the location of a particular point on an 8 1/2" X 11" sheet of paper, you would need to measure how far from the left edge that point is, then how far from the top edge it is.

A digitizer does this for you. It tells you how far horizontally (the X-axis) and how far vertically (the Y-axis) that point is from the edge of the paper.

The Network 3 Controller

The Radio Shack Network 3 Controller (catalog number 26-1212) was a networking system designed for use in classrooms. First appearing in the 1983 catalog, the Network 3 Controller cost $599.00. Unlike the earlier Network I> and Network 2 Controllers, which worked with more than one type of TRS-80 computer, the Network 3 Controller only supported the Model III or Model 4 in Model III mode.

From the description in a 1983 Radio Shack catalog:

The Network 3 Controller enables up to 16 Model III student stations to choose from lessons stored on a teacher’s “host” system. This frees the instructor from repeatedly loading programs into individual stations. And scores are automatically stored on the host disk for later review as lessons that generate student record keeping are completed. The Network 3 also allows computer science students to learn Disk BASIC on a non-disk Model III. That means you get the features of a disk-equipped computer, but at about half the price!

PT-210 Portable Data Terminal

The TRS-80 PT-210 Portable Terminal (catalog number 76-1001) was a mobile dumb terminal that provided a way for travelers to access remote computers while on the road. Introduced by Radio Shack in late 1982 for a price of $995.00, the PT-210 was promoted with the slogan “Now there’s a TRS-80 you can take with you on business trips!”"

The PT-210 weighed 15 pounds and came in a briefcase-style case. It contained a full-size 53-key keyboard, an acoustic coupler that communicated at 110 or 300 baud, and a “whisper-quiet” thermal printer. The catalog description stated:

The Network I Controller

The Radio Shack Network I Controller (catalog number 26-1210) was an early networking system for the TRS-80. Introduced on March 1, 1980, the Network I Controller (originally called the TRS-80 Model I Network I) cost $499.00 and was primarily designed for classroom use.

The Network I concept, described as “teacher-centric,” was based around a disk-based Model I (used by a teacher) connected through a Network I Controller and cassette cables to cassette-based Model I’s (used by students). Up to sixteen student computers could be connected over a distance of up to thirty feet. From the announcement in the TRS-80 Microcomputer News:

The Model III to 4 Upgrade Kit

The TRS-80 Model 4, introduced in 1983, was 100% software compatible with its predecessor, the TRS-80 Model III. A cassette-based Model 4 behaved identically to a cassette-based Model III and could run all Model III software. But a disk-based Model 4 could also run new Model 4 software that exposed features unique to the Model 4, such as extra memory and a larger text resolution. For Model III owners who wanted to run the new software but were unwilling to discard their Model III, Radio Shack offered the Model III to 4 Upgrade Kit.

The Model III to 4 Upgrade Kit (catalog number 26-1123) originally cost $799.95 and was introduced at the same time as the Model 4. It could convert a disk-based Model III into a disk-based Model 4, capable of running all Model 4 programs. One early Model 4 advertisement stated that “Model III disk system owners can get all the new Model 4 features by adding our upgrade kit.”

The Model III to 4 Upgrade Kit consisted of several parts:

Mayday Uninterruptable Power Supplies

Mayday was a line of uninterruptible power supplies for the TRS-80 and other computers. It was sold by Sun Research (originally Sun Technology), a division of Phase-R Corporation.

Phase-R Corporation was located in New Durham, New Hampshire and experienced frequent problems with poor power quality and frequent outages. They originally developed the Mayday to protect the office TRS-80’s, describing it as “designed and developed using a complete TRS-80 system.” Sun Research introduced the first Mayday model in 1980.

Echo-80 Speech Synthesizer

Street Electronics Corporation sold a variety of speech synthesizers with the Echo name. The Echo II, the Apple II version, was the most popular, but they also sold versions for other computers. As of 1982, there were four versions:

  • Echo-80 for the TRS-80 Model I and III
  • Echo II for the Apple II
  • ECHO-100 for S-100 computers
  • ECHO GP (General Purpose) for any computer with a RS-232 or parallel printer port (including a TRS-80)

TC-8 Cassette System

The TC-8 Cassette System was a hardware add-on from JPC Products that provided faster and more reliable cassette storage for the TRS-80 Model I. Advertised as “The Poor Man’s Floppy”, the TC-8 provided features similar in many ways to the Exatron Stringy Floppy. The TC-8 could store up to 300K on an single 30 minute cassette tape. It increased the standard TRS-80 cassette data rate from 500 baud to nearly 3000 baud. It also promised much greater reliability, “less than one bad load in a million bytes.”

The TC-8 was derived from the TC-3, a similar cassette system that JPC Products created in 1978 for 6800 computers. When introduced in 1980, the TC-8 cost $69.95 for a kit and a $99.95 for a fully assembled version. Those prices soon increased to $89.95 for the kit and $119.95 for the fully assembled version. The JPC Products advertisements recommended that buyers consider the kit version, saying:


The E/RAM was a high-resolution add-on for the TRS-80 Model I. Introduced in 1980 for a price of $349.95, the E/RAM was designed and manufactured by Keyline Computer Products from Tulsa, Oklahoma. It was sold by Vern Street Products, also in Tulsa.

The E/RAM (an acronym for Extended Random Access Memory) contained 6K of video memory. It increased the TRS-80 graphics resolution to 256 by 192, with the high-resolution graphics overlaying the text screen. The graphics could be enabled and disabled using either software or a hardware switch.

The E/RAM came in a steel case measuring 2 1/2″ high, 6″ wide, and 12″ deep. The self-contained unit sat next to the Model I and installed in a straightforward way:

The SubLOGIC 50/T80

The SubLOGIC 50/T80 was a high-resolution add-on for the TRS-80 Model I. It was created by SubLOGIC, a company better known to TRS-80 users for their T80-FS1 Flight Simulator.

Here is the text of the 1980 product introduction:

The SubLOGIC 50/T80 system is a high performance professional graphics display system designed to be used directly with the TRS-80. It provides the high-resolution graphics capability which the 80 lacks—the kind of graphics needed for scientific, engineering, and educational applications. Dense drawings, graphs, and even alphanumerics can be put on the 50/T80’s 256 by 240 dot screen. The 50/T80 has the support of SubLOGIC’s 2D and 3D graphics packages, which are powerful and easy to use. They operate easily from BASIC as well as assembly language.