US Robotics Courier V.Everything x2 Addendum, Руководство пользователя

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Client Modems
x2 client modems can receive data at speeds up to 56 kbps and send data at
V.34 speeds. The following products are examples of U.S. Robotics Client
Modems:
•
Courier™ V.Everything™ with x2
•
Sportster® with x2
•
Analog Modem Pools or NETServer with x2
Server Modems
The digital x2 modems that client x2 modems connect to are called server x2
modems. Server modems can send data to client x2 modems at speeds up to 56
kbps. A server must have a “digital” interface to the PSTN. This digital
interface can be in the form of a “trunk-side” T1, Primary Rate Interface (PRI) ,
or Basic Rate Interface (BRI). The following products are examples of client x2
modems:
•
Courier I-modem with x2 (in Server Mode)
•
Quad Modem 5.0/5.1 (in Server Mode)
•
MP I-modem or NETServer I-modem with x2
Making x2 Work
To use x2, the client x2 modem must connect to a server x2 modem. If clients
attempt to connect to ISPs that do not use x2, the client modem will negotiate
the next available modulation. For example, an x2 client modem calling into an
ISP that only supports V.34, the modem will only negotiate the highest v.34
connection rate. The maximum V.34 connection speed is 33.6 kbps.
When a client x2 modem connects to a server x2 modem, the path through the
telephone network between the modems is subject to the following conditions
for an x2 connection to be made.
A Digital Connection At One End
ISPs or online services must have a digital connection to the PSTN. Most major
online services have digital connections to the PSTN.
Only One Digital-to-Analog Conversion
There can be only one digital-to-analog conversion in the telephone network
between the x2 server modem and the x2 client modem.