Modemulator User Guide
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71
of
113
Troubleshooting and FAQs
General
If you have trouble with the USR3520/USR803520 first try the following:
Try cycling the power off and on, then repeat the setup process.
Make sure the correct COM port was selected.
Consult the cellular service provider to verify that the Modemulator base unit is setup properly.
Make sure the power supply is plugged in to an operational power outlet, and that the power
supply is also securely plugged into the unit.
Verify all cables and adaptors are correct for the type of ports.
Verify that the Modemulator card is fully seated in the base unit.
When power and interface cables are connected, type
AT<Enter>
to see if
OK
appears on the
terminal.
What are displayable characters?
"Displayable characters" are all ASCII characters from 20h thru 7Eh.
What are programmable characters?
All 3 of the programmable characters (Escape, Xon, Xoff) can be any ASCII character 00h thru 7Fh (0 thru
255 decimal).
What are dial modifier characters?
Dial modifier characters are any non-numeric displayable character following a dial (D) command.
Examples of common dial modifier characters used in dial-up modems are:
P T , ; " W @ / R ! L S $
Also punctuation characters like - ) ( and <space> are dial modifier characters.
Dial modifier characters (except comma, colon, and L) in Modemulator dial commands that initiate cellular
connections are ignored. Dial modifier characters in Modemulator dial commands that are forwarded to an
attached dial-up modem are processed by the dial-up modem.
Can I use the SIM from my phone for Modemulator?
Generally no. The SIM from your phone is not provisioned for peer-to-peer data connectivity, which
Modemulators require in order to emulate the analog PSTN and dial-up modems.
However, depending on how your SIM is provisioned, it may allow connectivity to the Internet, and
Modemulator can use this type of connectivity when operating in single-ended mode to originate a
connection to the IP address of a TCP/IP server.
