User's Manual

User’ s Manual
Page 5
Require Safety Check - Upon completion of any service or repairs to this product, ask the
service technician to perform safety checks recommended by TurboComm to determine that
the product is in safe operating condition.
Overview
The modem provides you with high-speed data communications over the television cable
network by following the widely accepted DOCSIS/MCNS standards being developed by the
Multimedia Cable Network System (MCNS) consortium. Those standards offer a combination
of high performance and interoperability among many of the cable system operators in North
America.
How does a cable modem work?
As you know, digital signals are represented by high and low electrical voltage levels. And how
fast these levels can switch and still be transmitted is determined by the "bandwidth" of the
transmission system. The pair of wires used in a telephone connection have greatly limited
bandwidth, because of their electrical characteristics. So what we do is connect a device called
a modem between the computer output and the 'phone line. The modem generates an
electrical wave whose strength and phase change in step with the highs and lows of the
computer's digital output. It's because of the "smoothness" of the resultant signal that a higher
data rate can be transmitted.
A cable modem MOdulates and DEModulates electrical signals in the same sense that the
telephone modem does. However, since coaxial cable can carry much higher wave
frequencies, cable modems are far more sophisticated. Their internals can include a tuner, a
bridge, a router, an encryption/decryption device, an SNMP agent and an Ethernet hub.
Furthermore, none of the activity caused by these circuits and codes disturbs your regular
cable TV reception.
How does a cable modem connect to a computer?
The 10BaseT Ethernet connection used by TurboComm is emerging as the most popular. This
connection has been used for years to allow business computers to talk to each other in a LAN
(Local Area Network).
The new DOCSIS standard may change this in the future. But for now, an Ethernet card must
be installed in your computer for the TurboComm Cable Modem to work.