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Name Modified Size Downloads / Week Status
Totals: 10 Items   105.7 kB 51
README 2014-04-13 16.4 kB 77 weekly downloads
UPDATES 2014-04-08 18.2 kB 77 weekly downloads
jcblock.c 2014-04-08 37.3 kB 55 weekly downloads
truncate.c 2014-03-06 16.7 kB 55 weekly downloads
blacklist.dat.example 2014-03-06 2.5 kB 33 weekly downloads
whitelist.dat.example 2014-03-06 966 Bytes 1010 weekly downloads
tones.c 2011-02-04 11.2 kB 44 weekly downloads
makejcblock 2010-10-17 188 Bytes 33 weekly downloads
common.h 2010-09-19 1.2 kB 44 weekly downloads
callerID.dat.example 2010-09-19 1.2 kB 33 weekly downloads
Program: jcblock A program to block telemarketing (junk) calls. RECENT ACTIVITY: (04/2013): Several people have been successful running the program on a Raspberry Pi processor using a USB modem. The modems that have been used successfully are: US Robotics USR805637 and TRENDnet TFM-561U. There is a good writeup on the details at: http://weeklytechforum.com/2013/03/28/ block-unwanted-calls-with-a-raspberry-pi/ (12/2013): A minor change was made to the truncate.c file to cause data file record truncation after nine months instead of after one year. See the 28 December, 2013 entry in the UPDATES file for details. (02/2014): Code was added that emits a fax tone to a black- listed caller. This feature is optional and is designed to work with fax modems. This option will cause some predictive dialers to reject the number and remove it from their call list. See the 20 February, 2014 entry in the UPDATES file for details. (02/2014): Added code to add a tag to a call record before it is written to file callerID.dat. The tag indicates how the program handled the call. See the 23 February, 2014 entry in the UPDATES file for details. (03/2014): Made provision for permanent blacklist records. These records will not be removed by the routines in the terminate.c file when they are called. See the 5 March, 2014 entry in the UPDATES file for details. (04/2014): Changed the method to terminate a call. The new code is faster, so a blacklisted call is terminated after just one ring. The telephone touch pad '*-key' method to add a call to the blacklist may now be used after the second or third ring. See the 8 April, 2014 entry in the UPDATES file for details. MODEM SELECTION: I have been using the USRobotics model 5686G modem since October 20, 2010 and have seen no errors. I have therefore decided to recommend using it instead of the Zoom 3048 modem. I used the Zoom modem during most of the development work on this project. However, late in the testing I discovered that occasionally it did not deliver caller ID data between the first and second rings. I tried two 3048 units and saw the same result. I also upgraded the firmware in one of them with no effect. I sent email to Zoom and got no reply. If you have a Zoom 3048 modem, definitely use it for evaluation of the jcblock program. It will demonstrate all functionality of the program and you can start building your blacklist. The symptom you will see when the modem fails to deliver caller ID is that a call that would normally be blocked by an entry in the blacklist will be passed through. To get error free performance, you will need to purchase(~$90) a USRobotics 5686G modem. If you test the program with other modem brands, please report your results (good or bad) using this site's mailing list or by contacting me directly from this project's website. I will post any useful reports I receive. Thank you...WSH PROGRAM DESCRIPTION: This program connects to a serial port modem and listens for the caller ID string that is sent between the first and second rings. It records the string in file callerID.dat. It then reads strings from file whitelist.dat and scans them against the caller ID string for a match. If it finds a match it accepts the call. If a match is not found, it reads strings from file blacklist.dat and scans them against the caller ID string for a match. If it finds a match to a string in the blacklist, it terminates the junk call. The program also updates the date field of a matching whitelist or blacklist entry. Entries that are old may then be identified so that they may be removed. Note that the program will operate with only a blacklist.dat file defined. A whitelist is not required. Functions to manage the truncation (removal) of records from the blacklist.dat and callerID.dat files are present in file truncate.c. Records in the blacklist.dat file that have not been used to terminate a call within the last nine months are removed. Records in the callerID.dat file that are older than nine months are removed. The operations are performed every thirty days. Alternatively, entries in the .dat files may be edited manually. An additional feature is supported by functions in file tones.c. The program will add a record to the blacklist.dat file for the current call if the operator presses the star (*, asterick) key on a touch tone telephone handset during an allotted time period. The program detects the tone via a microphone placed near the modem speaker. Functions in file tones.c detect the presence of tones (941 Hz and 1209 Hz) produced by pressing the star (*) key. If an answering machine is installed on the same line this feature must be restricted to be active only if a call is answered after the second or third ring (the answering machine *must* also be set to answer on the fourth or later ring). If an answering machine is not installed on the line the star key feature is available for calls answered after the second or later ring. This option is controlled by a conditional compile flag (see the 09/24/10 UPDATES file entry for more details). Also see the NOTE: in the file concerning an ALSA version conditional compile selection. The program requires a serial modem that can deliver caller ID and contains a speaker. The recommended unit is the USRobotics model 5686G. It will return caller ID if it is sent command: AT+VCID=1. Note that the modem is used just to detect a call's caller ID and the star key tones; the modem's normal communication function is not used. The program may be terminated by sending it a SIGINT (Ctrl-C) signal or a SIGKILL signal. The program runs on a standard PC (it was written and tested on a Dell Dimension B110 running Ubuntu). The features supported by functions in files truncate.c and tones.c may be removed by disabling conditional compile flags DO_TRUNCATE and DO_TONES, respectively, in file jcblock.c. The default serial port specifier is: /dev/ttyS0. The program will accept an option to select a different port. The syntax of the call is: jcblock -p /dev/portID The entire program may be compiled with the following command: gcc -o jcblock jcblock.c tones.c truncate.c -lasound -ldl -lm Linux installations may or may not install the libasound library. It is usually installed in /usr/lib. Also, the tones.c file includes file asoundlib.h, which is usually located in directory /usr/include/alsa. If not installed, they can be by using the distribution's package manager. For example, for an Ubuntu distribution, the Synaptic Package Manager may be used to install alsa-base, to install the library, and alsa-source, to install the source files. If /usr/include/alsa is not yet present install libasound2-dev. It is also a good idea to install alsa-utils in case testing/debugging of the sound interface is needed. Here is a full list of the alsa packages I have installed on my Ubuntu 10.04 machine (you can show the ones installed on your machine by entering 'alsa' in the Synaptic Package Manager's Quick Search: window): alsa-utils alsa-base alsa-source libasound2 libasound2-doc libasound2-dev libasound2-plugins libsdl1.2debian-alsa linux-sound-base gstreamer0.10-alsa bluez-alsa libao2 No doubt some of these are not needed for the jcblock program, but if you install all of them, jcblock should run. If jcblock is run on a desktop or laptop, a microphone must be placed near the modem's speaker and turned on. The volume level must then be adjusted so that when the star key is pressed, the audio generated causes the program's tone filter thresholds to be exceeded. Mic audio volume may usually be set by a Preferences option. For Ubuntu the path is: System|Preferences|Sound. Then make sure the proper sound device is selected under Hardware. The mic volume may then be set under Input. The setting depends on the position of the mic relative to the modem's speaker. The slider is quite sensitive. Another way is to use the alsamixer program: choose the sound interface (F6) and the Mic slider (arrow keys). Using this program you have a numeric setting displayed that can be reused. Remember to keep the phone you answer with away from the mic, since the mic will respond to the tones received by the handset! For continuous use, the program should be run on a low-power single board computer so that it can be left on all the time. More on the whitelist: As a result of operational experience it became evident that the addition of a whitelist capability would be helpful. The whitelist file (whitelist.dat) holds entries containing the telephone numbers of calls the user definitely wants to accept. The program checks for caller ID matches of these entries first. If a match is found, the blacklist check is bypassed and the call is accepted. The issue came up when it was discovered that some telemarketers use cell phones! For cell phone calls, the 'NAME =' field in the caller ID string is usually: 'Cell Phone XX', where XX is the originating state designator (e.g., CA for California). So using the 'NAME =' field as the search string in a blacklist entry would cause all cell phone calls from the indicated state to be blocked! In addition, the telemarketers use several cell phones (probably as employees come and go), so using the 'NMBR =' field in the caller ID as the search string does not catch new cell phone callers. Adding a whitelist partially solves this problem. With a whitelist, the user can include entries that contain the cell phone numbers of calls they definitely want to receive from a specific state (e.g., CA). Then the cell phone 'NAME =' field for the state (e.g., 'Cell Phone CA') can be used as the search string in a blacklist entry. With this arrangement all cell phone calls from the state will be blocked *except* the ones with numbers present in the whitelist. As another example, a person might want to receive calls from just certain numbers and no others (an elderly person, for example). In that case the records for the numbers of interest would be placed in the whitelist and a single record placed in the blacklist that contains a field that is present in all caller IDs (e.g., 'NMBR'). Then all calls not matched by records in the whitelist would be terminated. Country codes: The USRobotics (and probably other modems) must be sent a country code command if the country of use is other than USA (the default). The command syntax is: "AT+GCI=XX\r", where XX is the country code. The codes for the USRobotics modem are as follows (check your modem 'Command Set' documentation for confirmation): Austria 0A Hungary 51 Norway 82 Belgium 0F Iceland 52 Poland 8A Cyprus 2D Ireland 57 Portugal 8B Czech and Slovak Federal 2E Israel 58 Spain A0 Republic Denmark 31 Italy 59 Slovakia FB Estonia F9 Latvia F8 Slovenia FC Finland 3C Liechtenstein 68 Sweden A5 France 3D Lituania F7 Switzerland A6 Germany 42 Luxembourg 69 Turkey AE Greece 46 Malta B4 United Kingdom B4 Netherlands 7B The command should be sent in the init_modem() function after the modem reset command (ATZ) is sent (the location is indicated in the listing). Other program changes may be needed to conform to non-USA country telephone systems. Real-time prototype system: The photo shows a prototype jcblock system consisting of a USRobotics 5686G modem and an eBox-3300 Server-in-a-box (SIB) purchased from EMAC, Inc. The SIB contains a Vortex86DX System-on-a-Chip that implements most of the functions of a standard x86 PC. The system shown draws about 6 watts, so the cost of running it 24/7 is minimal. The eBox came with a version of Linux installed that did not have the ALSA audio interface. Since this application requires a microphone to implement the star (*) key feature, I chose to boot a stripped down version of Knoppix from a USB memory stick. I started with the version included on a DVD with the book: "KNOPPIX HACKS, 2nd Edition", O'Reilly, ISBN:978-0-596-51493-8 and "remastered" it (trimmed its size) using the procedures described in hacks #109 and #110 (in addition, I removed all documentation and Linux source code, etc.). The result was a version that would fit on a CD, for backup. The procedure results in a knoppix.iso file which I then used to make USB boot version using a procedure I found at: http://www.knoppix.net/wiki/USB_Based_FAQ Note that if you don't need the star key feature, the program will run just fine on the version of Linux that comes with the eBox. The Knoppix version has the additional advantage that the gcc compiler, libraries and include files needed to compile the program are present on the target. The knoppix system did not contain an Ethernet module that was compatible with the Vortex86DX chip. The needed module is r6040.ko. It may be downloaded from a site reached via: http://dir.filewatcher.com/d/Debian/all/net/r6040-source The module depends on module mii.ko, which was included with Knoppix. The photo shows the Knoppix USB stick installed in a front USB socket. All application files are contained on the USB stick installed in the back. This provides non-volatile storage for them, which is needed for the callerID, blacklist and whitelist files. The eBox BIOS may be instructed to boot from the USB stick. During the process of constructing the knoppix.iso file, as described above, I installed a script called startApp in /etc/init.d and link S99startApp to it in /etc/rc2.d to provide for automatic startup of jcblock (the grub loader menu.lst file instructs grub to boot to level 2). Script startApp mounts the application USB stick on /mnt and then runs a setPorts script on it to perform various system administration functions not included in the knoppix.iso build (some that were forgotten!) before starting the application program jcblock. As a result, the entire system starts up and runs when the power is turned on without the need for manual operations via a terminal and keyboard. Since sshd and ftpd daemons are started, all maintenance may be performed via the Ethernet interface. It is especially convenient to maintain data files using a Firefox plugin called FireFTP. So the system may be maintained through a GUI from any computer that can run Firefox (e.g., Windows, Mac, etc.). There is the issue of interrupting a write to flash memory by a power failure (or turn-off), which could cause damage to the memory. The application program is normally blocked in a serial port read operation, waiting for a call. The only time writes occur is for a short time immediately after a call is received. So, if the unit is turned off at other times, no damage will occur to the USB memory. On the outside chance that memory is damaged, the application USB memory stick may be easily replaced. Since Knoppix loads into a RAM disk, no damage can occur to it. Wrap-up: That about summarizes my experience with this project. The system runs continuously at our home and terminates junk calls indicated in the blacklist file. After about six months the number of junk calls we received decreased to only a few a week as the telemarketers removed us from their call lists. The easiest way to get started with this project is to just compile the program and run it on a standard PC. It works fine that way, but you have to leave your PC on all the time to be useful in terminating calls. If you do that anyway then you are all set! Otherwise you should eventually consider installing it on a dedicated low power embedded computer system similar to the one I described above. If your PC does not have a serial port, a PCI serial port card or USB serial port adapter can be installed at minimal expense.
Source: README, updated 2014-04-13