ZyXEL Communications ALC1248G - Manual (Page 13)

ALC1248G User’s Guide
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H A P T E R
1
Introducing the ALC1248G
This chapter introduces the ADSL2/2+ line card's general features, factory default settings and
hardware.
1.1 ALC1248G Overview
The ALC1248G ADSL2/2+ Line Card is perfect for ISPs or large building applications
seeking to provide high bandwidth broadband services to subscribers while minimizing costs.
One ALC provides ADSL service for 48 subscribers over existing telephone wiring, thus
avoiding the cost and hassle of installing new wiring.
The line from the user carries both the ADSL and the voice signals. For each line, the splitter
card separates the high frequency ADSL signal from the voice band signal and feeds the
ADSL signal to the line card, while the voice band signal is diverted to the central office
switch or PBX (Private Branch Exchange).
Use the Telco-50 connector pin assignments in
Section 2.3 on page 24 along with the
directions and safety warnings in the IES User's Guide to install the line card and make the
necessary connections.
See the MSC User’s Guide for detailed information on configuring the line card.
1.2 ADSL Standards Overview
These are the ADSL standards and rates that the ADSL line card supports at the time of
writing. The actual transfer rates will vary depending on what the subscriber’s device
supports, the line conditions and the connection distance.
Table 1 ADSL Standards Maximum Transfer Rates
STANDARD MAXIMUM DOWNSTREAM MAXIMUM UPSTREAM
G.dmt 8160 Kbps 1024 Kbps
ANSI T1.413 issue 2 8160 Kbps 1024 Kbps
G.lite 1536 Kbps 512 Kbps
ADSL2 12000 Kbps 1200 Kbps
ADSL2 Annex M 12000 Kbps 2400 Kbps
ADSL2+ 25000 Kbps 1200 Kbps
ADSL2+ Annex M 25000 Kbps 2400 Kbps