Demystifying RS232 and VGA: A Layperson‘s Guide

Have you ever opened up an old computer and wondered about those unfamiliar ports? Maybe you glimpsed some cryptic RS232 or VGA markings among dusty connections whose purpose eludes modern understanding. I‘ve been there too!

As a long-time hardware analyst, my job exposes me to computing antiques running interfaces modern devices dropped years ago. And I enjoy unraveling their mysteries!

In this guide, I’ll clarify exactly what functionality the aging RS232 and VGA standards delivered to early computers – and why they eventually got left behind technologically. My goal is making this knowledge more accessible for the everyday user.

Why Learn about RS232 & VGA?

Understanding the capabilities RS232 and VGA introduced helps us appreciate the computers we take for granted today.

Maybe you inherited a dust-covered IBM PC/AT with a serial mouse connector. Or you spot those familiar monitors with the big blue VGA port in older office buildings. When faced with tech oddities like these, learning a little legacy tech history goes a long way!

Once you grasp the baseline functions and limitations that led to RS232 and VGA, you gain useful perspective for why modern interfaces like USB and HDMI connect things differently under the hood. Appreciating the ingenuity behind old technology ultimately allows us to see how far computing has come!

Connecting Devices Before RS232

To comprehend the purpose of RS232 serial connections, one must understand what came before it.

Early computers relied on parallel ports for attaching printers, tape drives, and various input terminals. But these kludgy interfaces depended on locking multiple connectors perfectly in sync to maintain steady communication. This made adding new peripherals expensive and error-prone.

Later ASCII serial connections eased this strict timing requirement by packaging data into sequential bits. However, these links operated inefficiently, only pushing data in one direction. They also required costly converter modules to communicate with most peripherals.

There had to be a better way… one avoiding parallel timing issues AND wasteful one-way communication between devices.

RS232 – Ushering in Plug-and-Play Convenience

The new RS232 standard emerging in the 1960s finally delivered amajor connectivity breakthrough.

via serial lines, RS232 allowed affordable bi-directional data exchange between peripherals and computers without needing perfect sync. This introduced true plug-and-play expandability for the first time!

By embedding clock data alongside information, RS232 enabled self-contained communication channels. This freed external devices from depending on system-wide timing schemas. Any RS232-equipped terminal could interface with a host reliably at speeds up to 20 kilobits per second thanks to clever asynchronous techniques.

While later revisions pushed speeds higher, RS232 brought the foundational protocols making today‘s ubiquitous cross-device interoperability possible.

Limitations of Early Video Standards

Similar to device connectivity, early video graphics depended on inflexible standards ill-equipped for advancing display technology.

CGA/EGA graphics processing constrained resolution to 640 × 350 pixels while concentrating pixel data into a low 4/16 color palette. This forced graphical simplicity in early PC software.

Yet more sophisticated graphical interfaces were emerging. And display technology progressed towards larger screens, more colors, and more pixels at budget prices.

There needed to be a new graphics standard extending beyond what existing video circuitry supported.

VGA – Enabling GUI Environments

Thus, IBM introduced the Video Graphics Array (VGA) standard in 1987 to usher personal computing graphical capabilities into modernity.

VGA succeeded by providing display circuitry for crisper 640 × 480 resolutions at flexible 256 color depths. This enabled intricately-detailed graphics, realistic images, and smooth animations compared to EGA/CGA.

Crucially, it was backward-compatible to earlier standards. So applications leveraged VGA automatically while retaining CGA/EGA compatibility.

As GUI operating systems arose, VGA’s boosted graphics delivery and backward-compatibility empowered software developers. More vibrant, responsive desktops became feasible through this incremental improvement.

RS232 vs VGA Connectors – Spot the Differences!

SpecificationRS232 ConnectorVGA Connector
Pin Count9 pins15 pins
Transmission ModeSerial – 1 bit at a timeParallel – Multiple simultaneous signals
Maximum Speed20 kbps up to 256 kbps>200 MHz bandwidth
Primary FunctionBi-directional communication Display video output
Key ApplicationsMice, modems, terminals, other peripheralsPowering CRT & early LCD monitors

With only 9 pins available for coordinating two-way peripheral communication, RS232 prioritizes efficient serial data packaging over channel capacity. Smaller connector size but slower speeds reflect its die-signed role transmitting device instructions rather than pushing visual data.

In contrast, VGA’s wide 15 pin interface and high analog bandwidth conveys the exacting timing performance necessary for painting complex graphical imagery onto display screens rapidly. More contacts ensure signaling accuracy across dedicated red, green, and blue video pathways tying directly into CRT circuitry.

So in summary – RS232 specialized in lower-bandwidth device handshaking while VGA channeled its pins towards unidirectional, graphics-focused video output.

The Eventual Downfall of RS232 & VGA

While crucial in their time, RS232 and VGA faced extinction as computing demands eclipsed their capabilities.

Consumer thirst for products offering greater speeds, smaller sizes, and software/hardware integration fueled rapid technological change leaving RS232 and VGA outdated within decades.

The RS232 Situation

By the early 2000s, PCs completely replaced RS232 links with USB connections.

USB 1.0 already delivered over 1000 times RS232’s maximum speed. And later USB 2.0 operated 250 times quicker than that! Such extreme speed enhancement rendered RS232 obsolete for most applications.

Further, USB relies on cheap thumb-like connectors smaller than RS232 ports. This eased size constraints in modern compact computer designs.

And USB communicates bi-directionally like RS232 BUT ALSO provides power over the bus. So devices no longer need separate AC adapters for basic operation. This improved plug-and-play convenience.

Only industrial/scientific gear needing basic slow telemetry maintain niche RS232 relevance today thanks to easy terminal access. Elsewhere, it has completely relinquished to USB’s superiority.

VGA Loses Relevance

Similarly, VGA ceded relevance once GPUs shifted from analog to purely digital graphics output.

New standards like DVI, HDMI and DisplayPort surpass VGA using high-precision digital imaging. 2560 x 1600 resolutions at 120 hertz now fit comfortably within their considerable bandwidths.

Digital signals also carry both audio AND video. So achieving home theater sound immersion got easier. And advanced copy protection came built-in – absent from VGA connections.

Finally, digital linkage All journeys end. But paths continue arising, built atop progress made by those before.

So rather than dismiss RS232 and VGA connections as arcane or obsolete, I encourage you to appreciate them as ambassadors from an evolutionary past that made possible the computers we use today.

Still Have Questions?

I hope demystifying some legacy technology gives perspective on computing‘s continual growth trajectory. Please ask below or contact me with any other questions! I‘m always happy to decode old-school interfaces and explain why we use what we use now.

At the end of the day, no successful standard gets left behind without good reason. New use cases arise. Culture shifts. And better technologies address emerging needs as they always have. RS232 and VGA positively impacted computing during their heyday. The march into the future walks atop their shoulders.

Did you like those interesting facts?

Click on smiley face to rate it!

Average rating 0 / 5. Vote count: 0

No votes so far! Be the first to rate this post.

      Interesting Facts
      Login/Register access is temporary disabled