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The TimeOut-2400 is a versatile timer and AC power switch. It is controlled by RS-232 commands or telephone ring signals. It is designed to control the power of a remote personal computer and/or modem.
The core of the TimeOut-2400 is a MicroChip PIC12C508 RISC micro-controller, operating at approximately one million instructions per second. It performs the timing functions, controls a power relay, monitors a telephone line for ring signals, and manages 2400 baud communications.
The TimeOut-2400 alternates between an "ON" state and an "OFF" state. The "ON" time can be indefinitely long, and as short as three minutes. The "OFF" time can also be indefinitely long, and as short as one second. The default "ON" time is indefinitely long. The default "OFF" time is 10 seconds. When power is first applied to the unit, it starts a default "ON" cycle, and the "ON" timer is disabled.
The relay which controls the power is rated at 8amps at 120/240 volts AC. The load may be either resistive or inductive. There is no minimum load. The TimeOut-2400 switches power at a near-zero-voltage-crossing to minimize stress on the attached PC.
The TimeOut-2400 can be programmed to use any time for either state. Programming is done via half-duplex EIA-232 communications at 2400 baud. A simple programming syntax allows a user to set or examine any register, determine status, or to go to any state. An unanswered ring signal on the telephone line will also cause the unit to change state.
The PC supplies all power for EIA-232 communications, and the telephone line supplies power for the ring detector. Power for the TimeOut-2400 itself is obtained from the power line and is optically isolated from both the PC and the telephone line.
The communications link to an attached PC is a standard EIA-232 hardware interface. This allows the TimeOut-2400 to communicate with any operating system on the PC, including DOS, Windows, OS/2, Unix, or network operating systems.
The TimeOut-2400 is fully compliant with FCC Rules Part 15 and 68, and is listed under UL Standard 1950.
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II. Application Notes
There are a variety of potential uses of the TimeOut-2400. Some ideas are described below.
Most users of remote or unattended PC's are aware that on occasion, a PC will "lock up". When this occurs, remote communication is impossible and some on-site manual intervention is required. It may take some time to detect the failure, and even more time to restart the remote machine. In mission-critical applications, this time must be at an absolute minimum.
The TimeOut-2400 and a small program can remedy this problem. The program we supply (watchdog.exe) works under Windows 95/98/NT/2000. The program can set up the TimeOut-2400 with an "ON" time of five minutes and an "OFF" time of ten seconds. The communications interrupt is then enabled for the receipt of a "break". The interrupt handler will send a "start new on cycle" command when a "break" is detected.
The TimeOut-2400 will send a continuous "break" during the last minute before turning off the power to the PC. If the "break" interrupt is detected by the program, the PC must be operating normally, so the TimeOut- 2400 is reset for five more minutes by the "start new on cycle" command. Additional tests may be made at this time to ensure that all devices are working properly. The entire process will take less than 5 milliseconds for each four minutes. The TimeOut-2400 will acknowledge the receipt of the command over the communications line.
If the "break" is not received by the PC, the TimeOut-2400 will turn the power off at the end of the five-minute "ON" cycle. Power remains off for ten seconds, and is then restored. This power-off/power-on reset will restart the PC so than normal operation may continue. The entire operation is completely automatic, and if the PC recovered from its error condition, it was inoperative for less than five minutes.
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The TimeOut-2400 has a standard telephone line input which can be attached in parallel with a modem. If the modem does not answer an incoming call after nine rings, the TimeOut-2400 will turn the power off for ten seconds, and then turn back on. This completely resets the PC and/or modem. The number of rings can be programmed to any value. This function is available whether or not the "watchdog" is functioning, and can be implemented with no software or serial port connection.
The ring detector is FCC-compliant, and is compatible with ComShare, Versalink and Stealth line sharing devices.
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Some users have remote PC's that are only used on a fixed schedule (e.g., midnight to 6:00 a.m.), and they prefer to have the PC's powered off when not in use. Using watchdog.exe and the schedule.dat file, the PC will perform a smooth Windows shutdown at the scheduled DOWN time, and then turn the power off to the PC. The TimeOut-2400 will turn the PC back on at the scheduled UP time.
In this manner, the remote PC will be on during the scheduled "ON" time, and off during the scheduled "OFF" time. The schedule is maintained indefinitely, even in the event of power failures at the remote site.
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Watchdog.exe maintains a log of every reboot on a remote PC. The log contains the date and time of the reboot and the cause: power failure, watchdog, or other (including software-initiated reboots or manual reboots).
Analysis of this log can help in determining the types of problems being experienced by a remote PC.
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E. Automatic Location and Testing
Since the TimeOut-2400 has predefined responses to specific commands, it is possible to find out from a program whether a device is attached to a remote PC, and if so, what communications port it is attached to. Simple diagnostics can determine whether the device is operating properly, and if not, the device can be put in a disabled state.
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In many cases of remote maintenance of a PC, it is desirable to perform a power-off/power-on reset to bring the PC into a known state. This is particularly important in the installation of new operating systems and communication software.
Simply setting the "OFF" time in the TimeOut-2400 to ten seconds, and then issuing a "start new off cycle" command to the TimeOut-2400 will accomplish this. The power will be turned off to the PC for ten seconds and then turned on, performing a complete reset of the PC.
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G. Remote Extreme Temperature Monitor
Although not a primary function of the TimeOut-2400, it can provide an estimate of extreme temperature variations at a remote site. The oscillator speed will decrease 0.1 MHz for every 20-degree (Fahrenheit) temperature rise. The oscillator speed can be queried with the "display calibration" command. Thus if the calibration reading decreases from 40 (the nominal value) to 38, the ambient temperature at the remote site has risen by 40 degrees. High temperatures at the remote site will accelerate failures in the remote PC.
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Sending a "break" signal to the TimeOut-2400 for three seconds will force the TimeOut-2400 into a reset. The reset is identical to a power on reset. Output power is unaffected unless the reset was done during an "OFF" cycle.
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Any display monitor can become an "Energy-Star-Rated" device by attaching the TimeOut-2400 power output to the display instead of the PC.
Software similar to the watchdog software described above can also detect keystrokes on the PC, and will keep the display monitored powered up for some predefined time, perhaps thirty minutes. After the preset time, the attached display will be powered down until a keystroke is detected. For Windows 95, a standard screen saver implementation is available upon request
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J. External Equipment Power Controller
The high switching capacity of the TimeOut-2400 allows it to be used to control the power of a wide variety of external equipment, even a small air conditioner.
Simply disable the "ON" timer and "OFF" timer. Then instruct the TimeOut-2400 to start a new on or off cycle, depending on what is wanted.
This application also illustrates that the TimeOut-2400 only needs to be connected to a PC to send commands. Once the equipment has been turned on or off, it will remain that way until specifically commanded to change, or a power failure occurs (The TimeOut-2400 is reset when power is lost).
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On initial power-up, the TimeOut-2400 will calibrate its oscillator speed against the power line. This speed calibration is required to develop the timing constants for the 2400 baud communications since the micro-controller operates from an RC oscillator. Re-calibration will occur whenever a command is not understood.
The TimeOut-2400 will initialize the query register to 'A1' if it was a normal power-up reset, or to 'B1' if the reset was caused by an internal watchdog timer reset. A "break" sent to the unit for more than 2.3 seconds will cause an internal watchdog timer reset. The user registers are cleared, and are otherwise not altered except by user-initiated commands.
The TimeOut-2400 will then set the "ON" cycle time to the default of 23 hours, 59 minutes, 50 seconds and the "OFF" cycle time to the default of 10 seconds. The "ON" timer is disabled, and the ring count is set to a default of nine rings. An "ON" cycle is then started.
The microcontroller will continuously check for incoming data and decrement the timer counters once per second. When the timer counters reach zero, the timer counters are loaded with the "OFF" cycle time and the relay is energized, which turns the power output off. The "OFF" cycle counters are decremented each second, and when they reach zero, another "ON" cycle is started.
The TimeOut-2400 will always receive data over the communications line. For the device to respond, the RTS (request to send) line must be high, and the DTR (data terminal ready) line must be low. These two lines are used to provide power to the unit's transmitting opto-isolators.
The TimeOut-2400 continuously monitors the telephone line for the presence of a ring signal. When the number of rings exceeds the predefined value (default is nine), the TimeOut-2400 will change to the opposite state (usually "OFF").
The TimeOut-2400 will transmit a "break" (hold the PC RxD line high) during the last minute before cutting power to alert a host PC. The "break" will cease if the host PC begins transmitting, but will return every second until the timer is reset or expires. It also sends a 0x07 (BELL) character at the end of each ring.
Accurate timing is kept by counting the cycles on the power line (either 50 or 60 Hertz). This results in extremely precise long-term timing: an error of less than one second per month.
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B. TimeOut-2400 Commands
When incoming data is received, the TimeOut-2400 defers timing for a few seconds to allow the command to be received. The incoming command is first edited to ensure that it is a valid command. If the command is not a valid command, a response of "??" is sent back to the host PC. If the command is valid, it is executed immediately and the appropriate response is issued.
The command syntax is C [nn] <cr>, where C is a one-character command, [nn] is a two-digit optional operand, and <cr> is carriage return (0x0d).
The commands may be upper-case or lower case. Every command will have a response. If the command is not understood, the TimeOut-2400 will respond with "??". If the command has an operand, the response will be the operand if the operand was valid, otherwise the response is the current setting of the specified register. Commands are in three categories: Display, Set, and Action. Each command is described in the following sections.
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The TimeOut-2400 has thirty registers. The current contents can be displayed with the following "Display" commands:
Command Meaning
D<cr> | Display disable setting for current cycle
E<cr> | Display disable setting for next "ON" cycle
F<cr> | Display disable setting for next "OFF" cycleH<cr> | Display hours remaining in current cycle.
I<cr> | Display hours setting for next "ON" cycle.
J<cr> | Display hours setting for next "OFF" cycle.M<cr> | Display minutes remaining in current cycle.
N<cr> | Display minutes setting for next "ON" cycle.
O<cr> | Display minutes setting for next "OFF" cycle.S<cr> | Display seconds remaining in current cycle.
T<cr> | Display seconds setting for next "ON" cycle.
U<cr> | Display seconds setting for next "OFF" cycle.C<cr> | Display the calibration setting.
Q<cr> | Display the query register.(The "Query" register shows the current state of the TimeOut-2400, and how it got to that state. The query register is in the form Ln, where n is 1 for power on, and 0 for power off. "L" has the following definitions:
"A" means power up
"B" means internal watchdog reset
"C" means "W" command
"D" means "X" command
"E" means "Y" command
"F" means "Z" command
"G" means TimeOut
"H" means ring count exceeded)P<cr> | Display the previous contents of the Q register.
1<cr> | Display the user register.
R<cr> | Display the current ring count.
G<cr> | Display the ring count to change state.
A<cr> | Display the ring timer.Return to User Manual Index | Return to Home Page
G. Set Commands
Many of the TimeOut-2400 registers can be changed with "Set" commands.
Command | Meaning
Dnn<cr> | Set disable setting for current cycle to nn.
Enn<cr> | Set disable setting for next "ON" cycle to nn.
Fnn<cr> | Set disable setting for next "OFF" cycle to nn.
Hnn<cr> | Set hours remaining in current cycle to nn.
In<cr> | Set hours setting for next "ON" cycle to nn.
Jnn<cr> | Set hours setting for next "OFF" cycle to nn.Mnn<cr> | Set minutes remaining in current cycle to nn.
Nnn<cr> | Set minutes setting for next "ON" cycle to nn. (The next "ON" cycle must be for at least three minutes)
Onn<cr> | Set minutes setting for next "OFF" cycle to nn.Snn<cr> | Set seconds remaining in current cycle to nn.
Tnn<cr> | Set seconds setting for next "ON" cycle to nn.
Unn<cr> | Set seconds setting for next "OFF" cycle to nn.Gnn<cr> | Set the ring count to change state to nn.
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Command | Meaning
V<cr> | Report Firmware Version
W<cr> | Start new "OFF" cycle
X<cr> | Change state immediately
Y<cr> | Start new "ON" cycle
Z<cr> | Reset to power-on defaults and start "ON" cycle.The response to each of these commands is the two-digit firmware version followed by a carriage return (0x0D).
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A command must be sent completely within three (3) seconds. If it is not completed within that time, the TimeOut-2400 will respond with a "??".
The response to a Set command is the value stored. It is the value from the register, not just an echo of the command. Valid settings are from "00" through "99".
All responses by the TimeOut-2400 are terminated with a carriage return (0x0D).
Care should be exercised in using the "Set" commands for the current cycle (D, H, M, S) since these registers are being decremented every second. A recommended procedure is to set S to some arbitrarily high value (99, for example) then set D, H and M to the desired value, and finally set S to the desired value.
Although it is possible to set the "C" (calibration) register to some other value, subsequent commands will be unrecognized and force a re-calibration, returning the "C" register to its measured value.
Similarly, the "Q" register can be set to any value from zero to 99, but will return to the proper query setting whenever the TimeOut-2400 changes state or executes an action command.
Any register may be set to any value from zero to 99 with the exception that the "ON" time may not be less than three minutes. This gives the TimeOut-2400 its own "fail-safe" property, allowing an attached host PC enough time to fully reboot at the start of an "ON" cycle.
As a memory aid, the "CURRENT" cycle commands are D (Disable), H (Hours), M (Minutes), and S (Seconds). The "ON" cycle commands are one letter more for each of the commands, e.g., "I" instead of "H" for Hours. The "OFF" cycle commands are the next two letters alphabetically, respectively.
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1. Turn off the PC and plug the power cable on the PC into the TimeOut-2400. Connect the TimeOut-2400 power input to a UPS or wall socket with another PC power cable (not furnished).
2. Connect the RJ-11 connector from the TimeOut-2400 to the modem telephone output (Telephone) jack if you want to use the ring count feature.
3. Connect the DB-9 connector from the TimeOut-2400 to an unused COM port on the PC if you want to use the watchdog feature or to be able to program the TimeOut-2400. This should be COM1 if the internal modem is on COM2.
4. The hardware installation is now complete.
5. The power-on defaults for the TimeOut-2400 are to hold power on indefinitely. Power will be cut off for ten seconds after nine rings on the telephone line. No software is required for these features.
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Download the software package and follow the instructions contained in the package. The package is a self-extracting zip file.
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Once you have loaded watchdog.exe, you can type commands and see responses in the window. It is recommended that you print a copy of the User Manual for ready reference.
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V. Technical SpecificationsSpecifications are subject to change without notice. Please contact TimeOut Devices, Inc. if you have any questions.
Size: 2" x 2.6" x 3.9"
Weight: Approximately 5 ounces
Color: Black
Material: ABS Flame-Retardant ThermoplasticPower Input: IEC Male Connector
Power Output: NEMA 5-15R Receptacle on "D" model, IEC Female on "U" model
Communications: DB-9 female jack
Telephone: RJ-11 jack100/240 Volts
50/60 Hertz
8Amperes
Resistive or Inductive Load (no minimum)
Zero-Crossing SwitchingTemperature: 0 to 70 degrees Celsius
Humidity: 0% to 99%, non-condensing
Recommended for Indoor Use Only
Qualified for EnergyStar RatingPower Relay life over 1,000,000 switching cycles
Unit operating life more than 100,000 hours (over 10 years)
Long-term timing accuracy better than one part in 1,000,000The TimeOut-2400 generates, uses, and can radiate radio frequency energy and if not used properly, may cause interference to radio and television reception. It has been tested and found to comply with the limits for a Class A computing device in accordance with the specifications in Subpart J of Part 15 of FCC Rules, which are designed to provide reasonable protection against such interference when operated in a commercial environment. The TimeOut- 2400 has been tested and found to comply with part 68 of the FCC rules for telephone network connections.
Unit is constructed entirely of UL-recognized components, and complies with all applicable standards contained in UL Standard 1950. UL Listing has been obtained (File No. E189740).
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Last Update: 11/02/99
WebMaster: Jim Daniel, Email to jim@timeoutdevices.com
© Copyright 1999 TimeOut Devices, Inc.