DSCAlarm
Linksys WRTSL54GS
DSCMon[itor] - Web Interface and Binaries
TODOs
Started
- Finish developing dscmon.
- Finish web interface.
- `-> Add color option for zone labels
- Document dsc binaries in the "copy extra" area and the "script" area
Completed
Change dscsend to use the dsc.conf file.- Done.Have dscmon pass parameters to dsclog.- Done.Add code to read a log file in dscmon.- Done, it now uses the /etc/dsc.conf.Finish developing dsclog. As now I'm using cat /dev/tts/1 > dsc.log and I don't believe this is a good long term solution.- I have dsclog writing to the log file. It's primitive and will need refactoring later.Clean up and document scripts.- Done.Fix firewall issue (isn't bocking ssh)- Web interface is stubborn, so I added my drop to the S55knockd script.Fix serial communications problem- Ended up being a setup issue, so I changed the S15serial script.Finished dscsend to send proper packets to the serial port. It will calculate the proper checksum, etc.- Initial version done.
IT-100 Information
I use the IT-100 to connect to the keybus on the DSC alarm. The IT-100 gives me a RS232 port for bi-directional communications. The docs say that it only uses pins 2, 3, and 5 (Rx = Receive, Tx = Transmit, and SG = Signal Ground). By default, the baud rate is 9600, but it can be changed through the IT-100's protocol. There is no flow control. The settings are as follows:
| Baud Rate | Parity | Data Bits | Stop Bits | Hardware Flow Control |
|---|---|---|---|---|
| 9600 | None | 8 | 1 | None |
RS232 Information
Typical RS232 Pinout:
| Pin | Label | Function |
|---|---|---|
| 1 | DCD | Data Carrier Detect (Modem) |
| 2 | Rx/RxD | Receive Line |
| 3 | Tx/TxD | Transmit Line |
| 4 | DTR | Data Terminal Ready (Flow Control) |
| 5 | SG/GND | Signal Ground |
| 6 | DSR | Data Set Ready (Flow Control) |
| 7 | RTS | Request To Send (Flow Control) |
| 8 | CTS | Clear To Send (Flow Control) |
| 9 | RI | RI Ring Indicator (Modem) |
| Male Connector | Female Connector |
|---|---|
 |
|
- A low state is defined as anything =< -3
- A high state is defined as another => +3
- Anything between -3 and +3 is in the dead area
Communications Problem
Explanation
For some reason, my laptop will communicate with the IT-100 just fine, but my Linksys WRTSL54GS router with a TTL shifter will not communicate to the IT-100. Here's where it gets crazy: I can communicate just fine between the laptop and the Linksys router (still using the TTL shifter). The problem is that I need the Linksys router to communicate with the IT-100.
Research
Laptop pin states, port is closed.
- Pin 3: Low = -10
- Pin 4: Low = -10
- Pin 7: Low = -10
Laptop pin states, port is open and not connected to anything.
- Pin 3: Low = -10
- Pin 4: High = +10
- Pin 7: High = +10
Laptop pin states, port is open and connected to IT-100.
- Pin 2: Low = -5
- Pin 3: Low = -9
- Pin 4: High = +9
- Pin 6: High = +9
- Pin 7: High = +9
- Pin 8: High = +9
Laptop pin states, port is open and connected to Linksys.
- Pin 1: High = 8
- Pin 2: Low = -5
- Pin 3: Low = -9
- Pin 4: High = +8
- Pin 6: High = +8
- Pin 7: High = +9
- Pin 8: High = +9
Linksys pin states, port is closed.
- Pin 2: Low = -6
Linksys pin states, port is open and not connected to anything.
- Pin 2: Low = -6
Linksys pin states, port is open and connected to IT-100.
- All pins are low. Pin 2 carried about -2 volts, which is in the dead area.
Solution
I figured out that all I need to do was twist the Rx and Tx lines. Yup, a simple null modem adapter would have solved the issue all a long! I'm only guessing that my laptop worked because either the terminal program or the Belkin USB to Serial adapter was smart enough to switch the lines.
How to Communicate
I've used both minicom and microcom without problems. I haven't figured out how to send "\r\n" with either terminal, but I was able to do it from an echo. I basically ssh into the Linksys router twice (I guess I could use screen and switch back and forth). In one session I type the following:
cat /dev/tts/1
Then in the other session I echo the 001 packet, which asks for the current status, as such:
echo -en "\n00191\r\n" > /dev/tts/1
That's all there was to it!
How to get COM Settings
- setserial -g /dev/tts/*
- cat /proc/tty/driver/serial
- stty -F /dev/tts/1 -a
Setup COM Port
- See the following script: S15serial
If setup properly then it will look like the following:
root@orc:~# stty -F /dev/tts/1 -a speed 9600 baud; rows 0; columns 0; intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>; eol2 = <undef>; swtch = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase = ^W; lnext = ^V; flush = ^O; min = 1; time = 5; -parenb -parodd cs8 -hupcl -cstopb cread clocal -crtscts ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl ixon ixoff -iuclc -ixany -imaxbel -opost -olcuc -ocrnl -onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0 -isig -icanon -iexten -echo -echoe -echok -echonl -noflsh -xcase -tostop -echoprt -echoctl -echoke root@orc:~# cat /proc/tty/driver/serial cat: cat: No such file or directory serinfo:1.0 driver:5.05c revision:2001-07-08 0: uart:16550A port:B8000300 irq:3 baud:114583 tx:277 rx:0 RTS|DTR 1: uart:16550A port:B8000400 irq:3 baud:9593 tx:0 rx:0 RTS|CTS|DTR|DSR|CD