Introduction Flashcards
also known as Plain Old Telephone Service (POTS)
Public Switched Telephone Network (PSTN)
is the wired phone system over which landline telephone calls are made
Public Switched Telephone Network (PSTN)
The PSTN relies on ___
circuit switching
Maximizing the bandwidth of a medium
Multiplexing
Local exchange also called ___
Central Office
An E.164 International Number has the format :
Country-Code Area-Code Exchange-Code Line-Number
Idle or open circuit in the telephone circuit
On Hook
Closed circuit or in use
Off Hook
Ring-back signaling
440+480 with 2:4 cadence
Busy
480+620 with 1/2:1/2 cadence
Trunk busy
480+620 but 0.2:0.3 cadence
Receiver off-hook
1400+2060+2450+2600 with 0.1:0.1 cadence
Call duration consists of
set-up, voice and tear-down phases
When a subscriber moves from one cell to another in a cellular system, this is called a
Handoff
When a subscriber moves from
one city to another, this is
Roaming
coordinates the cellsites and
implements signaling and handoffs
Mobile Telephone Switching Office (MTSO)
worldwide standard for cellular voice
GSM
also uses the existing residential local loop technology. Inexpensive because no
need to pull new wires, but 1-pair voice-grade UTP is not designed for high-speed
transmission.
ADSL or Asymmetric Digital Subscriber Line
Downstream and Upstream speed for ADSL
Downstream: 3 Mpbs
Upstream: 512 Kbps
CATV originally meant
community antenna television
were originally built to extend the reach of TV signals and improve over-the-air TV reception
Cable Systems
Downstream and Upstream for digital signals over radio waves
Downstream: Headend-to-subscriber has 810 MHz of RF bandwidth
Upstream: Subscriber-to-headend has 37 MHz of RF bandwidth
brings high-speed
optical fiber lines to the neighborhood
Cable modem service
Bandwidth is shared by everyone in the neighborhood
Cable Modem Service
Downstream and Upstream for cable modem service
Downstream speeds up to 5 Mbps.
Upstream speeds up to about 1 Mbps.
