Introduction to the HotWire DSLAM
1-11
8000-A2-GB21-20
November 1997
97-15456b
HUB
.
.
.
10BaseT
End-user
System 1
End-user
System 2
End-user
System 32
POTS/DSL
NID
From Network
Access Provider
NID = Network Interface Device
DSL
5446
RTU
POTS
POTS
Splitter
POTS
Optional
For more information about the 5446 RTU, see the
HotWire 5446 Remote
Termination Unit (RTU) Customer Premises Installation Instructions.
Data Rates
The HotWire DSL card employs Rate Adaptive Digital Subscriber Line (RADSL)
devices based on Carrierless Amplitude & Phase (CAP) technology. The RADSL
speed is asymmetric. This means that the downstream rate (from the DSLAM to
the RTU) is faster than the upstream rate (from the RTU to the DSLAM).
You can manually set the speed (providing the line you are using can support the
specified speed) or set the mode to rate adaptive. When the mode is set to rate
adaptive, the HotWire DSLAM determines the line speed during the initial
handshaking session between the DSLAM and the RTU based on the local loop
length, the amount of noise on the loop, and the user-configurable upper and
lower speed limits.
The following are the maximum upstream and downstream data rates:
Maximum upstream data rate: 1088 kbps (1.088 Mbps)
Maximum downstream data rate: 7168 kbps (7.168 Mbps)
Data rates and data transmission distances vary depending on existing telephone
line conditions (i.e., the DSL cards measure performance during operation and
can adjust the upstream or downstream rate to match changing local loop
characteristics due to temperature, humidity, or electrical interference). Also, the
maximum data rate will be dependent on the RTU in use.
For a complete listing of the DSL card data rates and information on how to set
the line speed, see Chapter 6,
DSL Card Configuration, of the HotWire DSLAM
for 8540 and 8546 DSL Cards User’s Guide.
