Telemarketing (Junk) Call Blocker, Release 2.

Walter — Wed, 26 May 2010 14:43:05 -0000

A program to block telemarketing (junk) calls. The program uses a modem to collect the caller ID data received between the first and second rings of a call, and then stores it in a caller ID file. It then scans records in a blacklist file against the caller ID data. If a match is found, it sends off-hook/on-hook commands to the modem, which terminates the call.

The program runs on a standard PC that has a serial port to access the modem. If a PC does not have a serial port, an inexpensive PCI serial port card may be installed. For continuous operation a better solution is to run it on a low power embedded system similar to the one shown in the project's screenshots.

Release 2.0 includes additional features: 1) a whitelist file for calls you definitely want to accept, 2) a facility for automatically placing a call record in the blacklist by pressing key '5' on a touchtone phone handset, 3) a set of functions that truncate entries in the blacklist file that have not been used to terminate a call in the past year and to truncate caller ID file records that are older than a year. The latter two features may be optionally disabled.

After running the program for about six months (and building up the blacklist), only a few junk calls are received in a week, as telemarketers remove the called number from their call lists. More detailed information is available in the project's README file.

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Telemarketing (Junk) Call Blocker, Release 2.