#NFT whale is back 🐳 #eCash $XEC is #Bitcoin $BTC, again thank you to @Joseinnewworld https://t.co/8xcMxBKFrv pic.twitter.com/BFeZMEfsfz
— Gaexe (@gaexe_) March 12, 2025
Unguided Transmission Media (Un-Guided Transmission Data) is a media used to transmit data, where the direction from one end to the other end is spread, for example: wireless.
This communication sends signals into the air based on the electromagnetic spectrum.
Figure 3.30 Electromagnetic Spectrum
1. Radio Transmission
The development of radio communication technology is very rapid, the use of wireless-LAN is increasingly popular. To send data using radio communication there are several ways, namely:
- Directly radiated, in line with the earth's surface
- Reflected through the atmosphere.
Figure 3.31 Radio communication
This radio communication uses a special frequency so as not to cause interference with the use of other frequencies, the frequencies that can be used are called ISM bands. ISM stands for Industrial, Scientific and Medical. The frequencies that can be used include:
- 900 MHz
- 2.4 GHz
- 5.8 GHz
Figure 3.32 ISM Band
An example of using a Wireless-LAN device is shown in Figure 3.33.
Figure 3.33 Wireless-LAN Device
2. Satellite Communication
This communication is used for long distance or intercontinental communication. Where to connect it requires satellite technology. According to the distance, satellites can be categorized into:
- Geostationary
- Medium Earth Orbit
- Low Earth Orbit.
Figure 3.34 Satellite Communication
Satellite communication uses frequencies/bands.
Figure 3.34 Satellite Communication
Table 3.3 Satellite Working Frequency
| Band | Downlink | Uplink | Bandwidth | Permasalahan |
|------|----------|---------|-----------|---------------------------------|
| L | 1.5 GHz | 1.6GHz | 15 MHz | Bandwidth rendah, saluran penuh |
| S | 1.9 GHz | 2.2 GHz | 70 MHz | Bnadwidth rendah, saluran penuh |
| C | 4.0 GHz | 6 GHz | 500 MHz | Interferensi Teresterial |
| Ku | 11 GHz | 14 GHz | 500 MHz | Hujan |
| Ka | 20 GHz | 30 GHz | 3500 MHz | Hujan, harga perangkat |To contact another site, it can be done with a Very Small Aperture Terminal (VSAT). VSAT is a 2-way earth station with a parabolic antenna with a diameter of about 3 - 10 meters.
Figure 3.35 Satellite communication with VSAT
Guided Transmission Data Media
A medium used to transmit data, where the direction from one end to the other is clear, for example: cable.
1. Coaxial
Data cables that use copper material have 2 parts, namely:
- Core cable in the middle
- Stranded cables on the side are separated by an insulator.
Figure 3.21 Coaxial Cable
This cable uses a Bayonet Nut Connector (BNC) connector.
2. Twisted Pair
Twisted Pair cable, uses paired cables where the purpose is to eliminate the crosstalk effect. Widely used for LAN networks, because it is able to transmit large amounts of bandwidth.
Figure 3.22 Twisted Pair
This cable uses Registered Jack (RJ) series connectors, and depends on the category type. For category 2 using RJ11 while for category 5 and above using RJ45.
Table 3.1 List of Twisted Cable Categories
| Kategori (Category) | Data rate maksimum | Penggunaan |
|---------------------|-----------------------------|---------------------------------|
| CAT 1 | 1 Mbps (1MHz) | Analog voice, ISDN |
| CAT 2 | 4 Mbps | Token Ring |
| CAT 3 | 16 Mbps | Voice dan data 10BaseT |
| CAT 4 | 20 Mbps | 16 Mbps Token Ring |
| CAT 5 | 100Mbps 1000Mbps (4 pasang) | ATM |
| CAT 5E | 1000Mbps | Ethernet |
| CAT 6 | Mencapai 400MHz | Superfast broadband |
| CAT 6E | Mencapai 500MHz | 10GBaseT |
| CAT 7 | Mencapai 1.2GHz | Full Motion Video Teleradiology |Types of twisted cables according to their protection are divided into:
Unshielded Twisted Pair (UTP) Image
Shielded Twisted Pair (STP) Image
Screened Shielded Twisted Pair (S/STP) Image
Screened Unshielded Twisted Pair (S/UTP) / Foiled Twisted Pair (FTP) Images
For cable installation, follow the TIA/EIA-586-A/B rules.
TIA/EIA-586-B Image
TIA/EIA-586-A Image
If both ends use the same rules, the cable is called StraightThrough, whereas if they are different, it is called Cross-Over.
3. Fiber Optic
This type of cable does not use copper, but fiber optics. Where the signal that is transmitted is a beam of light. Capable of sending more bandwidth. Widely used for communication between Backbone, LAN at high speed.
Figure (a) Side view, (b) FO with 3 cores
Based on the number of light sources entering the FO core, FO cables are divided into 2, namely:
- Multimode, number of sources more than 1. Using core diameter with size 50 micron -- 100 micron
- Singlemode, number of sources 1. Using a core diameter of 2 -- 8 microns.
Table 3.2 FO Connector Types
PPP over SONET and SDH Circuits
Synchronous Optical Network abbreviated as SONET, Synchronous Digital Hierarchy abbreviated as SDH link, PPP over SONET or SDH connection is documented in RFC1619.
The base speed of PPP over SONET/SDH is STS-3c/STM-1 at 155.52 Mbps.
Understanding Asynchronous Transfer Mode (ATM)
ATM sends data in discrete chunks. It has multi logical connections over a single physical connection. ATM packets sent on a logical connection are called cells. ATM is able to minimize errors and flow control. ATM has a data rate of 25.6Mbps to 622.08Mbps.