18 6619-2202
… TDW-33 – Silent answering on predefined number
The TDW-33 is connected to a power meter which is remotely monitored. The TDW-33
shares the PSTN line with normal telephones which is preferred not to give a ring signal
when the meter is read.
The TDW-33 is configured to answer calls on the Caller ID received, the valid numbers
to answer is programmed into the TDW-33. There exists a number of standards for send-
ing Caller ID check which standard is used by your operator. The TDW-33 supports the
major implementations of Caller ID. In this example the DTMF Caller ID version is used.
Note that some implementations doesn’t give the possibility to make a silent answer
since the Caller ID is sent between first and second ring signal.
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 Westermo product range.
Configure the TDW-33 connected to the power meter
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=0 No auto answer on Ring signals
ATQ1E0&C1&K0&A1 Suitable for PLC communication
AT&W Save settings
AT*WACCTAB=1,”016428000”
AT*WACCTAB=2,”016480250” Set the valid A-numbers for automatic answering
AT*WCID=3,3 Set Caller ID to A-number answer with DTMF coded numbers