External Usb Modems; Basic Troubleshooting Steps - 3Com 3CP5610A User Manual

18 C 4: T
HAPTER ROUB LESHOOTING A ND
External USB
Modems
Basic Troubleshooting
Steps
H R
ELP ESOU RCES
4. For a V.92 connection, your modem must be connecting to a V.92
server. A pair of 56K modems will not connect to each other at V.92/56K
speeds.
Note: Current IC/FCC regulations limiting power may limit maximum
download speeds to 53,333 bps.
1. Is your modem turned on? When your modem is properly connected
to power and is turned on, the Power light on the front panel will be on.
2. Is your power supply connected properly to both your modem and an
electrical outlet? If it is, check the outlet with another electric device (like
a lamp) to be sure that you are getting power. Also, use the power supply
that came with your modem; other similar-looking power supplies may
be of different voltages and could damage your modem.
3. Are you using the proper cable to connect your modem to your
computer? If you are using your modem as a USB device, you will to need
to purchase a USB A to B cable. If you are using your modem as a serial
device, you will need to purchase an RS-232 serial/modem cable. Check
the packaging of the cable you bought. There are many computer cables
that look similar to an RS-232, such as a Null Modem cable, that will not
work correctly with this modem. Depending on whether you have a 9-pin
or 25-pin serial port on your computer, you will need either a DB9/DB25
or a DB25/DB25 serial cable. If you are using your modem as a USB
device, you need a USB A to B cable. See the following diagrams.
You need a
DB9F/DB25M
RS-232 serial cable.