May I set up a self operated vending machine before Shabbos knowing that gentiles will probably use it on Shabbos?

The only problem that need be considered is whether it is similar to asking a gentile to make a purchase on Shabbos. We have already learnt [1] that one may hand money to a gentile before Shabbos and request the purchase of a certain product, provided that one does not request it be purchased on Shabbos and there is an opportunity to buy it on a weekday, and that the gentile is rewarded for the action.

A vending machine can be compared to such a case, being that one is not telling a gentile to purchase an item on Shabbos. [2]

What if the machine only operates on Shabbos?

I still think that it would be permitted because the product is being purchased by the gentile solely for his own purpose, unlike the previous case where the item is being purchased for the Jew’s sake. Although the Jew will be making a profit on Shabbos, that in itself is not a crime. Seeing that a transaction is being made on Shabbos, i.e. the Jew is “collecting” money on Shabbos and transferring ownership of the bought item on Shabbos, Rav Yitzchak Weisz ztz”l in the îðçú éöç÷ lays down certain provisions and a rav must be asked.

Does that mean that one may own a store and have gentiles operating the store on Shabbos?

No, a store is far more complicated for various reasons. To name a few: a Jew is paying gentiles to work for him; a Jew is telling a gentile to do melacha for him; besides that there is also an element of chilul Hashem. There are many factors involved with a Jewish-owned store or a Jewish-gentile partnership and a competent rav must be asked whether it is permitted to operate on Shabbos.

What if there is a possibility that Jews will use the vending machine on Shabbos?

If the machine is positioned in a solely Jewish area or building it is far more complicated and it might not be correct to permit the machine to operate on Shabbos. However if the machine is used by Jews and gentiles alike and there is ample time to use the machine before or after Shabbos, there may be sufficient leeway to rely on one to permit the machine to operate on Shabbos, [3] but again, a rav must be consulted.

What about leaving a fax machine on or an answer phone to accept orders on Shabbos?

We find a machlokes amongst the poskim as to whether this is permitted. Some poskim say that the machine is being operated for the gentile’s own benefit and the Jew is not involved in any way in the melachos. Other poskim say that since melachos are being performed inside the Jew’s house, and when that happens one must usually prevent and protest against it, one cannot permit setting up such a machine before Shabbos. [4] As usual in such a case a competent halachik authority must be asked.

Is it permitted for a Jew in Israel to phone a gentile in the USA when it is no longer Shabbos in Israel but it is still Shabbos in the USA?

The majority of the poskim permit it as the Jew is not violating the Shabbos and as far as the Jew is concerned the Shabbos is already out. [5] One could argue and say that since in the gentile’s location it is still Shabbos and one is telling a gentile to ‘desecrate’ the Shabbos – but this is not so because the reasons prohibiting àîéøä ìòëå"í do not apply. For example: one reason is because if a Jew tells a gentile to violate the Shabbos, the Jew may do the same. This does not apply in this case because it is not Shabbos for the Jew and the Jew’s Shabbos will not be violated at any point.

Another is because ‘telling’ him is a violation of Shabbos speech. This does not apply either because it is not Shabbos for the Jew.