Lapisan fisik ( ) nyaéta hiji hambalan kahiji tina tujuh hambalan model OSI dina jaringan komputer, ogé mangrupa hambalan kahiji tina lima hambalan dina model rujukan TCP/IP. Lapisan ieu ngawangun layanan nu dipaké dina lapisan tumbu data (data link layer). 

The physical layer is the most basic network layer, providing only the méans of transmitting raw bits rather than packets over a physical data link connecting network nodes. No packet héaders nor trailers are consequently added to the data by the physical layer. The bit stream may be grouped into code words or symbols, and converted to a physical signal, which is transmitted over a physical transmission medium. The physical layer provides an electrical, mechanical, and procedural interface to the transmission medium. The shapes of the electrical connectors, which frequencies to broadcast on, what modulation scheme to use and similar low-level paraméters are specified here. An analogy of this layer in a physical mail network would be the roads along which the vans carrying the mail drive.

Physical signaling sublayer 
In a local area network (LAN) or a metropolitan area network (MAN) using open systems interconnection (OSI) architecture, the physical signaling sublayer is the portion of the physical layer that:
 interfaces with the medium access control sublayer (MAC) which is a part of the Data Link Layer
 performs character encoding, transmission, reception and decoding
 performs mandatory isolation functions.

Source: from Federal Standard 1037C

List of Physical layer services 

The major functions and services performed by the physical layer are: 
 Bit-by-bit node-to-node delivery
 Providing a standardized interface to physical transmission media, including 
 Mechanical specification of electrical connectors and cables, for example maximum cable length
 Electrical specification of transmission line signal level and impedance 
 Radio interface, including electromagnetic spectrum frequency allocation and specification of signal strength, analog bandwidth, etc.
 Specifications for IR over optical fiber or a wireless IR communication link
 Modulation
 Line coding
 Bit synchronization in synchronous serial communication
 Start-stop signalling and flow control in asynchronous serial communication 
 Circuit mode multiplexing, as opposed to statistical multiplexing performed at the higher level
 Establishment and termination of circuit switched connections
 Carrier sense and collision detection utilized by some level 2 multiple access protocols
 Equalization filtering, training sequences, pulse shaping and other signal processing of physical signals
 Forward error correction, for example bitwise convolutional coding
 Bit-interleaving and other channel coding

The physical layer is also concerned with
 Point-to-point, multipoint or point-to-multipoint line configuration
 Physical network topology, for example bus, ring, mesh or star network
 Serial or parallel communication
 Simplex, half duplex or full duplex transmission mode
 Autonegotiation

Conto lapisan fisik 
 Modem jaringan telepon V.92
 Lapisan fisik IRDA
 Lapisan fisik USB
 Firewire
 EIA RS-232, EIA-422, EIA-423, RS-449, RS-485
 ITU Recommendations: see ITU-T
 DSL
 ISDN
 T1 and other T-carrier links, and E1 and other E-carrier links
 10BASE-T, 10BASE2, 10BASE5, 100BASE-TX, 100BASE-FX, 100BASE-T, 1000BASE-T, 1000BASE-SX and other varieties of the Ethernet physical layer
 Varieties of 802.11
 SONET/SDH
 Antarbeunget GSM
 Lapisan fisik Bluetooth
 Lapisan fisik Wi-Fi IEEE 802.11x
 Etherloop
 Hybrid Fibre Coaxial

Conto kalengkepan hadwér (titik jaringan) 
 Adapter jaringan
 Repeater
 Hub jaringan
 Modem

Note: Physical layer
Associated with transmission of unstructured bit stréams over a physical link.
Responsible for the mechanical, electrical and procedural characteristics that
establish, maintain and déactivate the physical link.

Tempo ogé 
 Ethernet physical layer
 Line code

Rujukan 
 http://www.erg.abdn.ac.uk/users/gorry/course/phy-pages/phy.html
 http://www.tcpipguide.com/free/t_PhysicalLayerLayer1.htm

 

ru:Сетевая модель OSI#Физический уровень