computer science

Virtual COM port

Virtual COM port is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Virtual COM port rather than just read about it. In short: A virtual serial port is a software representation of a serial port that either does not connect to a real serial port, or adds functionality to a real serial port through software extension. Software virtual ports A software-based virtual serial port presents one or more virtual serial port identifiers on a PC which other applications can see and interact with as if they were real hardware ports, but the data sent…

Key takeaways

Virtual COM port belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Virtual COM port to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Virtual COM port from memory before moving on to harder problems.

Reference excerpt

A virtual serial port is a software representation of a serial port that either does not connect to a real serial port, or adds functionality to a real serial port through software extension.

Software virtual ports A software-based virtual serial port presents one or more virtual serial port identifiers on a PC which other applications can see and interact with as if they were real hardware ports, but the data sent and received to these virtual devices is handled by software that manipulates the transmitted and received data to grant greater functionality. Operating systems usually do not provide virtual serial port capability. Some virtual serial ports emulate all hardware serial port functionality, including all signal pin states, and permit a large number of virtual ports in any desired configuration. Others provide a limited set of capabilities and do not fully emulate the hardware. This technique can be used either to extend the capabilities of software that cannot be updated to use newer communication technologies, such as by transmitting serial data over modern networks, or to achieve data flows that are not normally possible due to software limitations, such as splitting serial port output.

Port sharing A serial port typically can only be monitored or transmitted to by one device at a time under the constraints of most operating systems, but a virtual serial port program can create two virtual ports, allowing two separate applications to monitor the same data. For instance, a GPS device which outputs location data to a PCs serial port may be of interest to multiple applications at once.

Network transmission Another option is to communicate with another serial device via internet or LAN as if they were locally connected, using serial over LAN. This allows software intended to interface with a device over a local physical serial port to instead communicate at long distance.

Bluetooth Bluetooth implements virtual serial ports over the Serial Port Profile. This is the standard way of receiving data from Bluetooth-equipped GPS modules, for instance.

Softmodems The drivers for a software-implemented modem create a virtual serial port for communication with the host operating system, since the modem is implemented entirely in the device driver and therefore there is no point where the serial data would be sent to the physical card.

See also Console redirection Serial over LAN Emergency Management Services (EMS) IPMI LAN Proxy server Shell shoveling

References

Worked examples

Example 1 — a first encounter with Virtual COM port

Start with the simplest possible case. Write down what Virtual COM port claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Virtual COM port before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Virtual COM port ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Virtual COM port

In research: Virtual COM port appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Virtual COM port in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Virtual COM port is common in secondary-school and first-year university syllabi. It links to neighbouring topics Internet Protocol based network software, Out-of-band management, Serial buses, so understanding it makes those chapters shorter.
In everyday life: Look for Virtual COM port outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Virtual COM port in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Virtual COM port means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Virtual COM port out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Virtual COM port in simple terms?

A virtual serial port is a software representation of a serial port that either does not connect to a real serial port, or adds functionality to a real serial port through software extension. Software virtual ports A software-based virtual serial port presents one or more virtual serial port identi…

Why does Virtual COM port matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Virtual COM port?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Virtual COM port.