16 6619-2202
… TDW-33 – Secure Call-back
The TDW-33 is connected to a PLC which one want to restrict access to. The TDW-33
can support access control through the Secure Callback function. In this example pass-
word and callback to a predefined number is chosen. The modem in the calling end is
here chosen to be a PSTN modem, but can be any of the PSTN, ISDN or GSM modem
from the Westermo product range.
The DTE serial speed between the PLC – TDW-33 and TD-36 – PC is assumed to be
9600 8N1 but can be chosen to fit the actual system requirement.
Configure the TDW-33
PSTN
Network
AT&F Set the unit to factory default
AT+IPR=9600 DTE baudrate 9600
AT+ICF=3,4 Character framing 8 data, 1 stop, parity none
ATS0=1 Auto answer after first ring
ATQ1E0&C1&K0&A1 Suitable for PLC communication
AT&W Store default settings
AT*WCB=4 Callback enabled, Password and callback number stored in
one or more positions of wcbtab
AT*WCBTAB=1,”+4670428000”,
”n3Y9kA6otYZu8”
Define callback number 1
When password 1 is entered number +4670428000 will be
called
AT*WCBTIME=10 Define delay time between hangup and callback
The TD-36 will wait 10 s after hangup to callback to allow
the analogue modem to hangup