Kada čujete izraz 'računalni priključak', na što pomislite? USB portovi? TCP/IP portovi? Može postati zbunjujuće. Postoje dvije klase portova – fizički i virtualni. USB priključak je primjer fizičkog porta, dok je TCP/IP port primjer virtualnog porta. 

Virtualni portovi brojčano nadmašuju fizičke portove pa ćemo početi s fizičkim. Obje se klase mogu naći na gotovo svakom elektroničkom uređaju. Telefoni, tableti, računala, čak i elektronički dijelovi u automobilima i drugim strojevima mogu imati obje klase. Za naše potrebe, u ovom članku ćemo reći računalo. Samo znajte da to može biti gotovo svaki uređaj.

Što je luka?^{(What Is A Port?)}

Dakle, što je luka? Ove priključke možemo nazvati utičnicama ili utičnicama, ali pravi izraz je port. Osnovna funkcija ovih portova je omogućiti da se jedan komad hardvera priključi na drugi kako bi mogli međusobno razgovarati. U tehničkom smislu, to su ulazno/izlazni (I/O ili IO) portovi. Broj priključaka koji uređaj može imati ograničen je dostupnim fizičkim prostorom.

Postoje dvije grupe portova - serijski i paralelni. Grupiranje se temelji na tome kako port dopušta komunikaciju. 

Serijski port može dopustiti prijenos samo jednog bita u isto vrijeme. Zamislite^(Think) vlak. Samo jedan dio vlaka može istovremeno biti na određenoj dionici pruge. Motor ide prije teretnog vagona, teretni vagon ide prije posljednjeg vagona. Ako se bilo koja dva od njih nalaze na istoj dionici pruge u isto vrijeme, to je olupina vlaka ili sudar. 

Isto vrijedi i za podatke koji teku kroz serijski port. Bit jedan^{(Bit one)} i bit dva ne mogu biti na istom dijelu kabela u isto vrijeme ili je došlo do sudara i stvari ne rade.

Paralelni port može omogućiti prijenos više bitova u isto vrijeme. Zamislite^(Think) autocestu s više traka. Svako vozilo na autocesti je malo. Na bilo kojoj određenoj dionici autoceste moglo bi biti 5, 10, možda 20 automobila odjednom, jedan pored drugog. To omogućuje mnogo bržu komunikaciju. Ako nije jasno kako, bit će.

Recimo da šaljemo poruku dvjema osobama, poput "Halo", vlakom i kamionom. Jednoj osobi šaljemo vlakom, a drugoj kamionom. Svako slovo pozdrava oslikano je na prednjoj strani kamiona i na prednjoj strani željezničkog vagona. 

Osoba koja čeka vlak, serijska metoda, vidjet će H na motoru, zatim E na sljedećem teretnom vagonu, zatim prvo L na sljedećem vagonu, zatim drugo L na sljedećem vagonu i O na konačni automobil.

Osoba koja čeka kamione na autocesti s 5 traka vidjet će kako svi kamioni stižu odjednom, jedan pored drugog, lijepo izgovarajući HELLO .

Vrste fizičkih portova^{(Types of Physical Ports)}

DE-9 ili RS-232 priključak – Opća upotreba^{(DE-9 or RS-232 Port – General Use)}

Možda ćete ih još uvijek vidjeti na nekim računalima, ali postaju sve rjeđe izvan industrijskog svijeta. Nekada su se koristili s mišem, tipkovnicom i nizom drugih uređaja.

PS/2 – General Use

Uglavnom viđen^(Seen) na starijim računalima, port Personal System/2 ( PS/2 ) najčešće se koristio za tipkovnice i miševe. Označeni su bojama – ljubičasta za tipkovnicu i zelena za miš. 

PS/2 portovi se još uvijek mogu vidjeti na računalima u objektima visoke sigurnosti. Posjedovanje samo PS/2 miševa i tipkovnica eliminira potrebu za USB priključcima. Gdje postoji USB priključak, postoji šansa da se podaci ukradu ili ubaci zlonamjerni softver.

USB priključak Opće informacije^{(USB Port General Information)}

Postoje 2 uobičajene glavne specifikacije za portove univerzalne serijske sabirnice^{(Universal Serial Bus)} ( USB ) koje se danas mogu vidjeti, USB 2 i USB 3 . Ove specifikacije odnose se na brzine prijenosa podataka, a ne na njihov fizički faktor oblika. Postoji nekoliko različitih faktora oblika koji će biti obrađeni dalje, u nastavku ovog odjeljka. 

USB 2.0 ima maksimalnu brzinu prijenosa podataka od samo 480 Mbps . Postoje različite verzije USB-a 3^{(USB 3)} , ali sve su vizualno vrlo slične osim nekih oznaka koje označavaju verziju. USB 3.0   je do 5 Gbps i USB 3.1 je do 10 Gbps , a USB 3.2 je do 20 Gbps . Da, dolazi i USB 4. USB 3^{(A USB 3)} uređaj radit će preko starijih USB 2 portova, ali će prenositi podatke samo brzinom USB 2 .

Vizualno se USB 2 tip A^{(Type A)} i tip B^{(Type B)} i njihove USB 3 kolege lako mogu razlikovati po boji bloka unutar konektora. Brži USB 3.0 ima plavi blok dok sporiji USB 2.0 ima crni blok. Druge vrste USB konektora nemaju takvu vrstu bloka. Ući ćemo u njihove stope prijenosa u njihovim vlastitim odjeljcima.

Ako želite više informacija o različitim vrstama USB kabela^{(different types of USB cables)} , imamo i članak za to.

USB tip A – Opća upotreba^{(USB Type A – General Use)}

Sigurno znate za USB priključak tipa A. ^{(USB Type A)}To je port sposoban za prijenos podataka i prijenos snage. Ispušta struju na oko 5 volti. Amperaža može biti u rasponu od 100 mA do 500 mA ili 0,5 Ampera. 

Deskriptor tipa A^{(Type A)} odnosi se na faktor oblika porta. To je najčešći pravokutni gdje polovica ima blok s konektorima, a druga polovica je otvorena za primanje odgovarajuće veze. Imamo i članak o popravljanju USB portova^{(fixing USB ports)} .

USB tip B – Opća upotreba^{(USB Type B – General Use)}

Najčešće viđen kod stolnih pisača, USB^{(USB Type B)} port tipa B ima četvrtastu rupu. Dolaze u USB 2 i USB 3 standardima. USB 2 pomalo podsjeća na završni profil staje, dok USB 3 pomalo nalikuje na kameni kamin.

USB tip C – Opća upotreba^{(USB Type C – General Use)}

Noviji faktor forme USB -a rješava smetnju zbog potrebe priključivanja kabela na pravi način. Bilo koji način će uspjeti. To je reverzibilni konektor. Također provodi napajanje na oko 5 volti, ali na višoj amperaži od USB tipa^{(USB Type A)} A. Može biti do 5 ampera^(Amps) . To čini brzo punjenje^{(fast charging)} jednom od njegovih značajki.

RJ-11 – Komunikacije^{(RJ-11 – Communications)}

Malo je vjerojatno da ćemo RJ-11 pronaći na uređaju osim ako se ne koristi za telefonsku ili faks komunikaciju. Da, to je telefonska utičnica. Može pasivno odašiljati električni signal, ali neke telefonske linije nose struju koja vas može snažno šokirati ako niste oprezni. Iako su staromodni, poštujte ih.

RJ-45 – Komunikacije^{(RJ-45 – Communications)}

Vjerojatnije nazvan mrežna utičnica, RJ-45 port je 8-pinski priključak za povezivanje uređaja na mrežu pomoću Ethernet kabela. Izgleda kao telefonska utičnica, ali samo malo širi.

3,5 mm TRS konektor – audio^{(3.5 mm TRS Connector – Audio)}

Oni se najčešće koriste za audio uređaje. Zeleni je za spajanje zvučnika ili slušalica. Ružičasta^(Pink) se koristi za mikrofone. Plava^(Blue) se koristi za izravnu vezu s audio uređaja. Također je poznat kao line-in. Postoje i druge vrste, ali one nisu uobičajene na kućnim uređajima.

VGA/SVGA Port – Video

Priključak Video Graphics Array ( VGA ) ili Super Video Graphics Array ( SVGA ) koristi se za povezivanje monitora ili projektora na računalo. VGA može pružiti rezoluciju do 640×480, a SVGA može ići preko 800×600. 

Obje vrste izgledaju identično. Izgledaju kao DE-9 , ali imaju 3 reda po 5 rupa, gdje DE-9 ima red od 5 i red od 4 ispod njega.

DisplayPort – video i audio^{(DisplayPort – Video and Audio)}

Ako vaše računalo ima utor koji izgleda kao pravokutnik s jednim obrijanim kutom, to je DisplayPort . To je 20-pinski konektor za priključivanje video uređaja. Također je sposoban slati zvuk putem kabela, pa ako uređaj koji povezujete ima zvučnike, trebao bi pokupiti zvuk i s vašeg računala.

HDMI – video i audio^{(HDMI – Video and Audio)}

Port High Definition Media Interface ( HDMI ) vrlo je popularan. To je također video port i sposoban je prenositi i audio signal. Nalaze se na većini računala i na mnogim televizorima.

To su različiti fizički portovi na koje ćete najvjerojatnije naići. Ako se luka koju tražite ne nalazi ovdje, postoji mnogo resursa za identifikaciju porta na Internetu^(Internet) .

Virtualni portovi^{(Virtual Ports)}

Postoji 65.535 virtualnih portova i svi su povezani s mrežnom komunikacijom. Svaki bi mogao imati drugačiju upotrebu, ovisno o vrsti podataka koji prolaze kroz njih. Ovi portovi se koriste za protokol kontrole prijenosa^{(Transfer Control Protocol)} ( TCP ) ili protokol korisničkih datagrama^{(User Datagram Protocol)} ( UDP ) ili oboje.

TCP se često spaja s internetskim protokolom^{(Internet Protocol)} (IP). Možda ste ga vidjeli kao TCP/IP . TCP se koristi za otvaranje veze između dva uređaja kako bi se podaci mogli prenositi. To čini tako da jedan uređaj dopre do drugog, a zatim se sklopi sporazum između njih za prijenos podataka. Ovo je poznato kao veza rukovanja. To može potrajati malo vremena.

UDP ne uspostavlja vezu za rukovanje. Tek počinje odašiljati. Brže je, ali budući da ne postoji nikakav dogovor o tome kako stvari učiniti, može doći do pogrešaka. 

U teoriji, bilo koja vrsta mrežne komunikacije mogla bi se dogoditi preko bilo kojeg porta. To bi postalo stvarno zbunjujuće s tisućama dostupnih portova. Dakle, pokušavamo slijediti standard kako bismo život učinili lakšim. Internet Assigned Numbers Authority^{(Internet Assigned Numbers Authority)} ( IANA ) ima registar portova i za što se oni koriste^{(registry of ports and what they are used for)} . 

Kada komunikacijski paket dođe u računalo, ono nosi informaciju o tome na koji port se želi spojiti. Ovo je način na koji računalo može reći što učiniti s tim paketima. Zbog toga možete pregledavati web stranice, prenositi datoteke i ispisivati ​​na cijelom istom mrežnom kabelu.

Možda ste vidjeli brojeve portova koji se koriste u IP adresama. To bi bio broj iza točke-zarez u IP-u kao što je 192.168.0.1:8080.

Slijedi popis portova na koje ćete najvjerojatnije naići. Ubacili smo posljednju za sve old school igrače^{(old school gamers)} .

Port	Description
20	File Transfer Protocol (FTP) data transfer happens on this port
21	File Transfer Protocol (FTP) control messages sent on this one
22	Secure Shell (SSH)
23	Telnet
25	Simple Mail Transfer Protocol (SMTP) for e-mail
53	Domain Name System (DNS)
69	Trivial File Transfer Protocol (TFTP) simplified version of FTP
80	Hypertext Transfer Protocol (HTTP)
8080	Hypertext Transfer Protocol (HTTP) Alternative
123	Network Time Protocol (NTP) for time synchronizing computers
143	Internet Message Access Protocol (IMAP) for e-mail
161	Simple Network Management Protocol (SNMP)
194	Internet Relay Chat (IRC)
443	Hypertext Transfer Protocol over TLS/SSL (HTTPS) Secure connections
465	Authenticated SMTP over TLS/SSL (SMTPS)
587	E-mail Message Submission (SMTP)
515	Line Printer Daemon (LPD) connects printers to a computer
666	Doom, the first-person shooter (FPS) game

Luke, Luke, Luke…^{(Ports, Ports, Ports…)}

Sada znate koji su najčešće viđeni fizički i virtualni portovi, kao i koji su njihovi poslovi. Označite^(Bookmark) ovo kao zgodnu referencu ili ispišite. 

Jeste li naišli na neke čudne portove? Imate li pitanja o drugim lukama ili trebate više detalja? Javite nam u komentarima. Tu smo da pomognemo.

HDG Explains : What Is a Computer Port & What Are They Used For?

When you hear the term ‘сomputer port’, what do you think of? USB ports? ΤCP/IP ports? It can get confusing. There are two classes of ports – physical and νirtual. A USB port іs an example of a physical port whіle a TCP/IP port is an example of а virtual port. 

Virtual ports outnumber physical ports so we’ll start with the physical ones. Both classes can be found on almost any electronic device. Phones, tablets, PCs, even electronic parts in cars and other machines can have both classes. For our purposes, we’ll say a computer in this article. Just know it could be almost any device.

What Is A Port?

So, what is a port? We may refer to these ports as jacks or outlets, but the proper term is port. The basic function of these ports is to allow one piece of hardware to be plugged into another so they can talk to each other. In technical terms, these are input/output (I/O or IO) ports. The number of ports a device can have is limited by the physical space available.

There are two groups of ports – serial and parallel. The grouping is based on how the port allows communications. 

A serial port can only allow for one bit to be transferred at a time. Think of a train. Only one part of the train can be on a specific section of track at a time. The engine goes before the cargo car, the cargo railcar goes before the last car. If any two of those are on the same section of track at the same time, that’s a train wreck or collision. 

The same goes for data flowing through a serial port. Bit one and bit two cannot be on the same section of cable at the same time or there’s a collision and things don’t work.

A parallel port can allow for many bits to be transferred at the same time. Think of a multi-lane highway. Each vehicle on the highway is a bit. On any specific section of the highway, there could be 5, 10, maybe 20 cars at once, beside each other. That makes for much faster communication. If it isn’t clear how, it will be.

Let’s say we’re sending a message to two people, like “Hello”, by train and by truck. We’re sending it to one person by train and another person by truck. Each letter of hello is painted on the front of a truck and on the front of a rail car. 

The person waiting for the train, the serial method, will see the H on the engine, then the E on the next cargo car, then the first L on the next car, then the second L on the next car and the O on the final car.

The person waiting for the trucks on the 5-lane highway will see all the trucks arrive at once, side-by-side, spelling out HELLO nicely.

Types of Physical Ports

DE-9 or RS-232 Port – General Use

You may see these on some computers still but they’re becoming less and less common outside of the industrial world. They used to be used with a mouse, keyboard, and a host of other devices.

PS/2 – General Use

Seen mostly on older computers, the Personal System/2 (PS/2) port was most commonly used for keyboards and mice. They’re color-coded – purple for the keyboard and green for the mouse. 

PS/2 ports may still be seen on computers in high security facilities. Having only PS/2 mice and keyboards eliminates the need for USB ports. Where there’s a USB port, there’s a chance for data to be stolen or malware to be injected.

USB Port General Information

There are 2 common major specifications for Universal Serial Bus (USB) ports that can be seen today, the USB 2 and USB 3. These specifications refer to the data transfer rates, not their physical form factor. There are several different form factors which will be covered further, below this section. 

The USB 2.0 has a maximum data transfer rate of only 480 Mbps. There are different versions of USB 3, but they’re all visually very similar other than some markings that indicate the version. USB 3.0  is up to 5 Gbps and USB 3.1 is up to 10 Gbps, and USB 3.2 is up to 20 Gbps. Yes, there is a USB 4 coming too. A USB 3 device will work through the older USB 2 ports, but will only transfer data at the USB 2 rate.

Visually, the USB 2 Type A and Type B and their USB 3 counterparts can easily be distinguished by the color of the block inside the connector. The faster USB 3.0 has a blue block where the slower USB 2.0 has a black block. The other types of USB connectors don’t have that kind of block. We’ll go into their transfer rates in their own sections.

If you’d like more information about the different types of USB cables, we’ve got an article for that too.

USB Type A – General Use

You definitely know of the USB Type A port.  It’s a port capable of transferring data and carrying power. It puts out electricity at about 5 volts. The amperage can range from 100 mA to 500 mA or 0.5 Amps. 

The Type A descriptor refers to the form factor of the port. It’s the most common rectangular one where half of it has a block with connectors and the other half is open to receive the matching connection. We’ve also got an article on fixing USB ports.

USB Type B – General Use

Most often seen with desktop printers, the USB Type B port has a square hole. They come in the USB 2 and USB 3 standards. The USB 2 one looks a bit like the end-profile of a barn, while the USB 3 one looks a bit like a stone fireplace.

USB Type C – General Use

The newer form factor of USB solves the annoyance of having to plug the cable in the right way. Either way will work. It’s a reversible connector. It also conducts power at about 5 volts, but at a higher amperage than the USB Type A. It can be up to 5 Amps. This makes fast charging one of its features.

RJ-11 – Communications

We’re not likely to find the RJ-11 on a device unless it is used for phone or fax communications. Yes, it’s a phone jack. It can passively transmit an electric signal, but some phone lines carry a current that can give you a solid shock if you’re not careful. Even though they’re old fashioned, respect them.

RJ-45 – Communications

More likely called the network jack, the RJ-45 port is an 8-pin port for connecting devices to a network using an Ethernet cable. It looks like a phone jack, but just a bit wider.

3.5 mm TRS Connector – Audio

These are most commonly used for audio devices. A green one is for connecting speakers or headphones. Pink is used for microphones. Blue is used for a direct connection from an audio device. It’s also known as a line-in. There are other kinds but they’re not common on home devices.

VGA/SVGA Port – Video

The Video Graphics Array (VGA) or Super Video Graphics Array (SVGA) port is used for connecting monitors or projectors to a computer. VGA can provide up to 640×480 resolution and SVGA can go over 800×600. 

Both types look identical. They look like the DE-9 but have 3 rows of 5 holes, where the DE-9 has a row of 5 and a row of 4 below it.

DisplayPort – Video and Audio

If your computer has a slot that looks like a rectangle with one corner shaved off, that’s a DisplayPort. It’s a 20 pin connector for attaching video devices. It’s also capable of sending audio over the cable, so if the device you’re connecting has speakers it should pick up the audio from your computer too.

HDMI – Video and Audio

The High Definition Media Interface (HDMI) port is very popular. It’s also a video port and it is capable of carrying the audio signal as well. These are found on most PCs and a lot of televisions.

Those are the different physical ports that you’re most likely to come across. If the port you’re looking at isn’t found here, there are lots of port identification resources on the Internet.

Virtual Ports

There are 65,535 virtual ports and all of them are related to network communications. Each one could have a different use, depending on the type of data going through them. These ports are used for Transfer Control Protocol (TCP) or User Datagram Protocol (UDP) or both.

TCP is often lumped in with Internet Protocol (IP). You may have seen it as TCP/IP. TCP is used to open a connection between two devices so that data can be transferred. It does this by having one device reach out to the other and then an agreement between them is made to transfer data. This is known as a handshake connection. That can take a little time.

UDP doesn’t make a handshake connection. It just starts transmitting. It’s quicker, but because there isn’t any agreement in place about how to do things, errors can take place. 

In theory, any kind of network communication could happen through any port. That would get really confusing with thousands of ports being available. So, we try to follow a standard to make life easier. The Internet Assigned Numbers Authority (IANA) does have a registry of ports and what they are used for. 

When a communication packet comes into a computer, it carries information about what port it wants to connect to. This is how the computer can tell what to do with those packets. It’s why you can view web pages, transfer files, and print all over the same network cable.

You may have seen port numbers used in IP addresses. It would be the number after the semi-colon in an IP like 192.168.0.1:8080.

Following is a list of the ports you are most likely to come across. We tossed in the last one for all the old school gamers out there.

Port	Description
20	File Transfer Protocol (FTP) data transfer happens on this port
21	File Transfer Protocol (FTP) control messages sent on this one
22	Secure Shell (SSH)
23	Telnet
25	Simple Mail Transfer Protocol (SMTP) for e-mail
53	Domain Name System (DNS)
69	Trivial File Transfer Protocol (TFTP) simplified version of FTP
80	Hypertext Transfer Protocol (HTTP)
8080	Hypertext Transfer Protocol (HTTP) Alternative
123	Network Time Protocol (NTP) for time synchronizing computers
143	Internet Message Access Protocol (IMAP) for e-mail
161	Simple Network Management Protocol (SNMP)
194	Internet Relay Chat (IRC)
443	Hypertext Transfer Protocol over TLS/SSL (HTTPS) Secure connections
465	Authenticated SMTP over TLS/SSL (SMTPS)
587	E-mail Message Submission (SMTP)
515	Line Printer Daemon (LPD) connects printers to a computer
666	Doom, the first-person shooter (FPS) game

Ports, Ports, Ports…

Now you know about the most often seen physical and virtual ports as well as what their jobs are. Bookmark this for a handy reference or print it out. 

Have you come across any weird ports? Do you have questions about other ports or need more details? Let us know in the comments. We’re here to help.

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