A modem modulates and demodulates analog signals to encode and decode digital data for transmission. There are different types of modems including telephone modems, which use telephone lines, cable modems, which use coaxial cable, and satellite modems, which transmit signals to and from satellites. Network interference can occur between devices operating on the same frequency channel (co-channel interference) or adjacent frequencies (adjacent channel interference). It can also be caused by electromagnetic interference between signals of the same or different frequencies. Troubleshooting is the process of identifying, diagnosing, and resolving problems in a computer network through collecting information, developing hypotheses, testing solutions, verifying fixes, and documenting results.

1. MODEM
NETWORK INTERFERENCE

2. WHAT IS MODEM?
• A modem is a network device that both modulates and demodulates analog
carrier signals (called sine waves) for encoding and decoding digital
information for processing.
• A modem transmits data in bits per second.
• Modem is necessary because it acts as a translator between the devices and
rapidly transmits the information.
• They are upgradeable through a software patch to meet almost any universal
standard.
• They enable high-speed downstream data transfers by digitally encoding all
downstream data while upstream runs at conventional rates of 33.6 kbps.

3. Types of Modem:
1. Telephone modem
• A computer is connected through telephone lines to access the network of
other computers.
• It is cheaper when compared to other modems because it does not have any
installation cost and also the monthly fee of a telephone modem is low. It
can be used in any house if a telephone network is provided.
• These modems are network devices that allow data communication between
two computers over voice-grade telephone lines.
• Telephone modems convert bits to analog signals for transmission through
physical channels. These also convert the analog signals in the local loops
into bits that are understandable by a computer.

4. 2. Cable modem
• Cable modem allow the access to high-speed data with the help of a cable
TV (CATV) network.
• Such modems are external devices connected to your PC with the help of a
standard 10 BASE-T ethernet card and twisted pair wiring.
• Cable Internet technology allows for transfer rates as high as 30Mbps.
• Cable modems are a prevalent type of hardware that connects computer
devices with your ISP. Differing from other types of modems, a cable
modem uses coax cable, the same infrastructure that brings television
programming to our business or homes, to proxy that connection, rather
than a telephone or DSL line.

5. 2. Satellite modem
• A device used to transmit and receive signals to and from a satellite. For
transmission to the satellite, the modem modulates digital data into a carrier
frequency for delivery to an upconverter, amplifier and antenna. For
receiving signals from the satellite, the modem converts the frequencies from
the downconverter into digital data.
• Satellite modem connects one side with MUX/EPABX and the other side
with RF Transceiver. It is mainly used to connect remote areas via satellite to
provide voice/data application support.

7. NETWORK INTERFERENCE
• Interference between heterologous viruses usually is produced by one virus
inactivating or inhibiting a host cell function required by the other virus.
• An alternative mechanism which can cause incompatibility of heterologous
viruses is based on the interaction of their gene products. This type of
interference occurs when two different viruses encode proteins that are
similar enough to form heterologous multimetric complexes.

8. TYPES OF NETWORK
INTERFERENCE
• Co-Channel Interference
• Adjacent Channel Interference
• Electromagnetic Interference

9. CO-CHANNEL INTERFERENCE
• The interference caused by transmitting at the same frequency by two or
more wireless systems is known as co-channel interference. In order to
handle huge number of calls with limited number of channels frequency
reuse concept is applied to the cellular system. In frequency reuse same
frequency is reused in multiple cells within their own boundaries without
causing any interference. These cells are known as co-channel cells.

10. ADJACENT CHANNEL
INTERFERENCE
• The interference caused to the desired signal (or channel) from adjacent
frequency signals is known as adjacent channel interference. This
interference is caused by leakage of frequencies from imperfect filters into
passband of desired channel. Moreover it is result of near-far effect.
• Adjacent channel interference can be reduced by careful filtering and channel
assignments by RF planners. In order to achieve this, frequency separation
between channels is kept large. Ensure that each mobile transmits smallest
power necessary to maintain good q

11. ELECTROMAGNETIC
INTERFERENCE
• Interference caused by EM signal at one frequency with the EM signal at the
same frequency or at the other frequency is known as EM interference.
Electromagnetic wave consists of electric field and magnetic field which are
perpendicular to each other. The EM waves travel in vacuum at the speed of
3 x 108 m/sec.
• EM interference can be between systems operating at the same frequencies
or at different frequencies. These interference types are known as co-
channel and adjacent/alternate channel interference.

12. TROUBLESHOOTING

13. Troubleshooting is the combined measures and processes used to identify,
diagnose and solve problems within a computer network. It’s a logical process
that network engineers use to resolve network problems and improve network
operations. Troubleshooting is an iterative process, the more data you collect
and analyze, the higher the likelihood of developing a correct hypothesis.
Troubleshooting steps:
1.Collect information
2.Develop a hypothesis
3.Test the hypothesis
4.Implement a fix
5.Verify the problem was solved
6.Notify the users
7.Document the fix

14. THANK YOU
~SUYASH CHAVAN
22203B0047