Monitors that are LCD (led crystal display) are prohibited because one who uses them is violating the work of writing, as with picture tubes. However, he does not violate the work of kindling a fire or cooking when turning it on.

One may ask, "Why is electron imagery considered writing since the electricity cannot continue generating without human assistance, and new electrons must constantly bombard the tube's coating to continue the imaging? At best it should only be temporary writing." The answer is that as long as continuity is to be expected and that to human eyes the writing appears to be continuous, it is considered permanent. The same reasoning applies to turning on an electric clock that runs on household electricity. As long as the flow of electricity is continuous and to be expected, then the electricity is a permanent part of the clock and with it the clock is considered complete.

By saving electronic information on a disk or tape, the value of the disk or tape is increased. This is a violation of the work of improving an implement since this improvement can last a long time. When the information is entered but not saved, this information can also last a long time in the computer, as long as its power remains on. However, since a computer is turned on and off after a short period, entering this information is considered using the computer and not improving it.

An improved alternate method of entering information for a doctor who is on call at a hospital is to use a battery operated computer. The advantage of this type of CPU is that the battery pack lasts for a short time; therefore, the CPU activity and the writing on its screen is temporary. By opening the CPU in an unusual way such as with a key or knuckle, he is making a temporary implement in an unusual manner. This is a double Rabbinical prohibition that is permitted for a seriously ill person. By typing in commands and information in an unusual way, such as with a penknife or with his knuckle, he is producing writing that is not permanent in an unusual manner. This is also a double Rabbinical prohibition.

Software can be designed to display and to fill in the various hospitals' forms needed for general use and for the doctor's specialty.

If there is a problem getting a non-Jew to enter the print command, he can request another Jew to press a penknife together with him on the print command. Two doing a work in an unusual manner is a double Rabbinical prohibition. In those hospitals that have a system integrated with the use of portable CPU's he may enter the save command in the same manner as he does the print command.

If the hospital system works with a mainframe and terminals, he should replace the terminal with a CPU. The CPU should have software that turns the image off, when it is not used for a short period of time. The subdirectory should be accessed before the Sabbath and the CPU should be attached to a timer to turn it off and then on, on Saturday evening after the end of the Sabbath. This would lend time to copy the file data before it is deleted. The AUTOEXEC.BAT file will be instructed to delete all the files in the subdirectory and then fill it with junk files so that the original files cannot be recovered. Consequently, Saturday evening, when the timer turns the CPU off and on again, the AUTOEXEC.BAT file deletes the subdirectory. Therefore, all information entered on the Sabbath is only temporary and if he enters the information in an unusual manner, it is a double Rabbinical prohibition.

During world war one and world war two the countries involved in espionage employed a secretive method of transferring information through microscopic writing. The writing appeared as a dots, readable only through powerful magnifying lenses. The question is, if the government demanded that he work in this art on the Sabbath, is he violating the Biblical work of writing or is the violation only Rabbinical since this writing is not discernable to the unaided eye? The answer is that the Biblical laws are dependant on natural vision. However, he violates a Rabbinical prohibition since he nevertheless is writing and in the process he sees himself forming letters. The dots that he is producing is unintentional and therefore a Rabbinical prohibition although they are discernable to the naked eye.

This same logic may be applied to writing with a chemical that is visible only when placed under a special light. This method of writing is used today by banks to conceal clients signatures and could be used by hospitals as an alternative method for signing various orders or reports. By writing with his left hand using this chemical he is only violating a double Rabbinical prohibition. However, it is easier to type in the information in an unusual way using a notebook computer. This invisible chemical method could solve the signature problem on the Sabbath.

It is permitted to use water filters that use an absorbent spongy like material that absorb the chemical impurities since these impurities are not discernible either before or after filtering. In places where the health authorities do not filter out dead organisms from the drinking water and the copepoda are discernible, it is permitted to pour water into a glass although the copepoda may be filtered out of the water. The reason for this is that when filling one glass of water at a time, it is not definite that from that glass a copepoda was filtered out. Although he opened the faucet, and if left open, enough water will have passed through the filter to be sure that a copepoda was filtered out on the Sabbath, this is not prohibited since it is not necessary to filter the unwanted water and all the components of the water are then considered part of the water, and regarding the work of separating, the filtering of the water is not considered separating waste from non-waste although it is doing this physically.

Using this logic, we permit washing dishes with filtered water although with the duration of the running water copepoda will be filtered out. The reason is that one is permitted to wash dishes with tap water without a filter since it is highly unlikely that any copepoda will remain on the moist dishes after washing and especially after drying them with a towel. Therefore, the copepoda are considered part of the water and not an unwanted impurity.

However, if one is filtering discernible impurities that are always found in the drinking water due to the poor condition of the pipes or other reasons, it is forbidden to open the faucet on the Sabbath for drinking or for adding to food. If he has no objection to wash dishes with the non-filtered water, then he may use the filtered water for this purpose for the same reason as stated before. If the faucet was left open before the Sabbath, one may use the water for drinking and to add to food.

It is forbidden to change the display window of a LCD display watch. If after changing the display it will return to the original display then it is considered temporary, and it is Rabbinically forbidden as writing. If it will not return to the original display then he violated a Biblical work.

Talking into a tape recorder does not produce audible sound and cannot be compared to talking into a microphone. It does store electronic data on a magnetic device and is considered as if an improvement was made in the cassette. There are hospital systems where the doctor records his report and the office workers type the report on forms. When finished they erase the recording. The recording is therefore, considered temporary. If he changes his voice when talking into the system he is temporarily recording in an unusual manner and it is a double Rabbinical prohibition.

When using a surgical laser knife many Sabbatical works are violated. When it is turned on the electrodes are heated red-hot and the liquified gas is evaporated. When cutting flesh with laser heat he is melting the flesh and cutting it to size. When mending a cut with laser heat he is melting the flesh and joining the sides. Turning on the laser is not a problem because this can be done by a non-Jew or timer. The problem is that only the skilled surgeon can guide the laser. If however, the laser can be guided by two people together, the prohibitions are Rabbinical and then it may be permitted to save a limb. If a seriously ill person is not treated now, and his illness may irreversibly deteriorate, or there is no other way to alleviate his pain except through the laser operation, then it would be permitted.

Video cameras that are designed for security systems continue without stop for days until they are serviced. By turning it on he violates the Rabbinical work of making a temporary implement and the Biblical work of permanently improving the recording tape, providing that the recorded information is useful to the security personnel. There are no discernable images or writing on the recorded tape.

Home video cameras are turned on and off at will; therefore, turning on the video camera is not considered creating a temporary implement. However, he violates the Biblical work of improving a video cassette when he records on it what he needs.

It is forbidden to walk in front of a camera of a security system because by doing so he causes his image to appear on the screen. This is comparable to printing his image. If it is done unintentionally it is Rabbinically prohibited. In order to attend to the needs of a hospital patient it is permissible to walk by the camera. This is because there is no other substitute for patient care in alleviating the patient's discomfort.

The reason people invest so much money in security systems is to protect their lives, property and for peace of mind. The questions are; To what extent is the danger? To what extent will the system prevent the danger? What is in danger? Are the prohibitions to turn the system on Biblical or Rabbinical? Then there is the problem of being locked in or locked out, because if he leaves or enters, the system will go off.

If the neighborhood is such that there is even only a small chance that there will be a break-in when people are home, then the law of saving a life on the Sabbath is applicable, providing that this alarm system may be able to save his life. Therefore, if for some reason the system was not set before the Sabbath it may be set on the Sabbath. One should always try to minimize the amount of violations transgressed in setting the system. One way of accomplishing this is to try to set the system in an unusual way.

If, however, it is highly unlikely that there will be a break in when people are home, then it is forbidden to violate any prohibition. If he feels uneasy without the system and it interferes with his rest, then he may ask a non-Jew to turn it on in an unusual way. However, if when no one is home there is a good chance that they may break in and the odds are that they will, then he may set the system by doing only a double Rabbinical prohibition or through a non-Jew, in order to protect his property. If the odds are that they will not break in, then he is not permitted to set the system.If he does not have peace of mind because he lacks the security protection then he may ask a non-Jew to set it in an unusual way.

When he is locked in or locked out because if he leaves or enters the system will go off, sometimes he may be permitted to trip the system. If he is locked in and cannot attend services he may ask a non-Jew to disarm the door in an unusual manner. If he must see a doctor because he is seriously ill he may disarm the door in an unusual manner. This would be permitted even if by closing the switch sparks are created. The reason is that the sparks are not needed and by doing it in an unusual manner it is a double Rabbinical prohibition. If when disarming the door he causes the LCD window display to print words such as "door disarmed," and this writing will remain that way permanently unless he does another action that will change it, it is a Biblical prohibition. The way to do it is to ask another person to help him disarm the door in an unusual way. If he cannot find help then he may disarm it alone in an unusual manner. The reason for this is that he does not have a doctor at hand to diagnose the seriousness of the illness and it could very well be that if not treated now it will cause him permanent damage.

If it is at night and he must trip the system that also turns on the lights, this is a Biblical work because he is benefitting from the lights. The way he is permitted to do this is to ask another person to help him open the door in an unusual way by using their shoes or a rag. This is a double Rabbinical prohibition and is permitted for a seriously ill person. If he cannot find help then he alone may open the door in an unusual manner if he is seriously ill.

Some homes have installed motion detector light switches that turn on a light bulb when passing by the house. It is permitted to walk through a street on a Sabbath evening even if there is a chance that he may trip these motion detector switches. The reason for this is that it is a questionable Rabbinical prohibition. If he does trip the switch he is permitted to continue walking even though this will extinguish the bulb. The logic for this is that if he continues standing there he violates a more severe prohibition of causing the bulb to burn longer. After discovering the places where these switches are installed he is thereafter forbidden to pass near there on the Sabbath and must avoid that area.

The same is true for one who is locked out. This situation is more serious because he may be in danger by staying out, or he may endure much physical discomfort and then the law of a seriously ill person will apply to him.

Turning on the system, by itself, is a Rabbinical prohibition of making a temporary implement or a temporary improvement in a building. This is because the system is turned on for a short period upon leaving and disarmed upon entering. Disarming the system, by itself, is not forbidden. There may be other Sabbatical works done when disarming the system such as creating sparks when closing the switch or producing writing on the systems display.

If he has to trip the system to enter and it is fully transistorized, working on a battery voltage transformer, as long as no hot sparks are produced and there is no LCD display, it is permitted if only the alarm goes off. The reason is that the prohibition is to produce sounds that he desires and not sounds that he does not want. Therefore, if he tests the system to hear if the alarm will go off, it is forbidden. If there is a device that calls the police when the system goes off, it is forbidden because he is making a temporary implement.

There are systems that use a set of mini LED bulbs as an information panel. If certain lights flash, that means that someone has entered that section of the house. This information implement is not needed for the household or even by the person moving from section to section in the house. Its use is to notify the owner about suspicious persons. Therefore, the one who is activating the system's lights has no use for this information and for him it is not an information implement. It is, therefore, permitted. However, it is preferable that he covers it for the Sabbath so that a person not versed in these laws will not suspect him of desecrating the Sabbath.

Someone who is witness to a burglary in a place whose residents are temporarily not in and consequently, there is no danger to life, may call the police through a double Rabbinical prohibition. This can be accomplished by first dialing the number with a penknife or knuckle. This makes the ringing a double Rabbinical prohibition. When talking to the police he changes his voice. This makes the sounds produced by talking a double Rabbinical prohibition. This cannot be permitted in Israel where the police are Jews unless there is some danger to life.

If he forgetfully presses a door bell and while his finger is still on the button he remembers it is Sabbath, he is forbidden to remove his finger in the usual way. The reason is that removing his finger is the same as closing a switch and sparks are created. Although by removing his finger he is also stopping the ringing of the bell, nevertheless, this by itself is permitted. If he uses his other hand to remove his finger, this is an unusual way of doing it and it is permitted as a double Rabbinical prohibition. Some bells have a light that turns off when the button is pressed and turns on when it is released. If it is dark and he is benefitting from its light then, it is a Biblical prohibition and he must ask another person to help him remove his finger. It is then a double Rabbinical prohibition.

An implement that is built to last six months or longer is a permanent implement and its completion is Biblically forbidden.

The basic components of a house are the floor, walls, roof, doors and windows. Any improvement in the floor as a floor or in the walls as walls or in the roof as a roof or in the door as a door or in a window as a window is a violation of the work of "building". Other types of improvements in these components are violations of the work of improving a building. One example of this work is boring a hole to install a lock or attaching shelves to a wall. Attaching the computerized control box of a security system to a wall is another example. Permanently setting the software to install the system is also considered improving a building even if it controls parts that are not attached to the building.