If you are looking behind a TV, cable box, antenna, or cable modem, the coaxial cable is usually the round cable that screws onto a matching threaded port. It looks different from Ethernet, HDMI, USB, and power cables.
Quick Answer
A coax cable usually has these visible features:
| Feature | What to Look For |
|---|---|
| Shape | Round cable, usually thicker and stiffer than many low-voltage wires |
| Connector | Threaded metal connector on many TV and internet cables |
| Center pin | One small metal pin in the middle of the connector |
| Common colors | Black, white, gray, or beige |
| Common location | TV wall outlet, cable modem, cable box, antenna, satellite receiver |
For home TV and cable internet, the most recognizable coax connector is the F-type connector.
Identification Checklist
Use this checklist if you are trying to identify a loose cable at home:
| Check | Coaxial Cable Clue |
|---|---|
| Connector shape | Round metal connector rather than a rectangular plastic plug |
| Center contact | One center pin or one center socket |
| Attachment style | Often screws onto the device for TV and internet use |
| Cable stiffness | Usually stiffer than Ethernet or thin audio cables |
| Jacket printing | May say RG6, RG59, RG11, 75 ohm, quad shield, CATV, or coax |
| Port label | Device port may say Cable, ANT, SAT, RF In, or Coax |
Do not rely on color alone. Coax cables can be black, white, gray, or beige depending on the installer and jacket type.
Where You Usually See Coaxial Cable
Coaxial cable is common in home entertainment and internet setups.
| Place | Why Coax Is There |
|---|---|
| Behind a TV | Connects TV antenna, cable box, or wall TV outlet |
| Cable modem | Brings cable internet signal from wall outlet to modem |
| Wall cable outlet | Connects the home to cable TV or broadband service |
| Satellite receiver | Connects satellite dish signal to the receiver |
| Outdoor antenna | Carries over-the-air TV signal indoors |
| CCTV system | Carries video from camera to recorder in older systems |
If a cable screws onto a round threaded jack, it is very likely coaxial cable.
How to Identify an F-Type Coax Connector
The F-type connector is the standard connector for many TV, cable modem, satellite, and antenna connections.
Look for:
- A round metal connector
- A threaded nut that twists onto the device
- A single center pin
- A matching threaded port on the TV, modem, wall plate, or cable box
The center pin is often the center conductor of the cable itself. Avoid bending or breaking it, because a damaged center pin can cause poor signal or no connection.
Coax Cable vs Ethernet Cable Appearance
Coax and Ethernet are often confused because both may be used in an internet setup. They are easy to tell apart by the connector, and the networking differences are covered in more detail in the coaxial cable vs Ethernet cable guide.
| Feature | Coaxial Cable | Ethernet Cable |
|---|---|---|
| Connector | Round metal connector, often threaded | |
| Plug shape | Circular | |
| Contacts | One center pin | |
| Common cable names | RG6, RG59, RG11 | |
| Typical use | Wall outlet to cable modem, TV, antenna | |
| Ethernet connector | RJ45 plastic plug | |
| Ethernet plug shape | Rectangular | |
| Ethernet contacts | Eight small metal contacts | |
| Ethernet cable names | Cat5e, Cat6, Cat6A | |
| Ethernet use | Router, computer, switch, smart TV, access point |
If the plug looks like a wider phone-style rectangular plug, it is probably Ethernet. If it screws onto a round threaded port, it is probably coax.
Coax Cable vs HDMI Cable Appearance
HDMI cable is also common behind TVs, but it looks very different from coax.
| Feature | Coaxial Cable | HDMI Cable |
|---|---|---|
| Connector shape | Round | |
| Connection style | Often screws on | |
| Signal | RF TV, antenna, cable modem signal | |
| HDMI connector shape | Flat, wide, trapezoid-like | |
| HDMI connection style | Push-in | |
| HDMI signal | Digital video and audio between devices |
Use coax for antenna/cable/satellite signal paths. Use HDMI between a TV and devices such as a streaming box, game console, Blu-ray player, or cable box.
What Is Inside a Coaxial Cable?
Even though you usually only see the outside jacket and connector, a coaxial cable has multiple layers inside.
| Layer | Purpose |
|---|---|
| Center conductor | Carries the signal |
| Dielectric insulation | Keeps the conductor centered and separated |
| Shield | Blocks interference and contains the signal |
| Outer jacket | Protects the cable |
This layered design is why coaxial cable is thicker and stiffer than many ordinary low-voltage wires.
What Does a Coax Wall Outlet Look Like?
A coax wall outlet usually has a small round threaded connector on a wall plate. It may be labeled “Cable,” “TV,” “SAT,” “ANT,” or not labeled at all.
You connect a coax cable by aligning the center pin with the hole and tightening the connector nut by hand. Do not force the connector if the pin is bent or the threads do not line up.
How to Tell If a Coax Cable Is RG6 or RG59
RG6 and RG59 can look similar. The easiest way is to check the printing on the cable jacket. If you are comparing outside diameter, the coax cable size chart explains the approximate differences.
Look for markings such as:
| Marking | Meaning |
|---|---|
| RG6 or RG-6 | Common modern TV/internet coax |
| RG59 or RG-59 | Older video or CCTV coax |
| 75 ohm | TV/video/cable-style impedance |
| Quad shield | Extra shielding layers |
| CL2, CL3, CM, CMP | Installation rating |
If the jacket is not readable, RG6 is usually slightly thicker than RG59, but measuring or reading the label is more reliable.
Common Mistakes When Identifying Coax Cable
One mistake is confusing coax with Ethernet. In cable internet setups, the coax cable connects the wall outlet to the modem, while Ethernet connects the modem or router to network devices.
Another mistake is assuming any round cable behind a TV is coax. Some power, audio, and component cables may also be round. The connector is the key: coax usually has one center pin and, for TV/internet, a threaded metal connector. For actual TV replacement cables, use the guide to the best coaxial cable for TV.
What Competitor Guides Often Miss
Many simple identification guides show only a TV coax cable with an F-type connector. That is useful for home users, but it is not the whole category. Coaxial cable can also use BNC, SMA, N-type, RCA, MCX, MMCX, and other connectors depending on the application.
For a home user, the most likely coax cable is RG6 or RG59 with an F-type connector. For an electronics technician, radio user, or lab user, a coax cable may be a 50-ohm RF cable with BNC, SMA, or N-type connectors. The cable is still coaxial because of its internal structure, even if the connector looks different from a TV cable.
FAQ
What does a coaxial cable look like?
A coaxial cable is usually a round cable with a single center conductor. For TV and cable internet, it often has a threaded metal F-type connector with a center pin.
What does a coax cable connector look like?
A TV or internet coax connector usually looks like a small round metal nut with one center pin. It screws onto a threaded port.
Is a coax cable the same as an Ethernet cable?
No. Coax has a round connector and usually one center pin. Ethernet has a rectangular RJ45 plug with eight small contacts.
Is a coax cable the same as an HDMI cable?
No. HDMI has a flat, wide push-in connector for digital audio and video. Coax is round and often screws onto a TV, modem, antenna, or wall outlet.
Where is the coax cable on a modem?
On a cable modem, the coax port is usually a round threaded metal connector. It is often labeled “Cable” or “Coax.”
What color is a coax cable?
coaxial cables are often black, white, gray, or beige. Color alone does not identify the cable type; check the connector and jacket markings.
Related Reading
For cable types, sizes, TV use, and internet use, see the full Coaxial Cable Guide.
