Learn Hardcore Japanese: tikokusitara tentyou ni renrakusurukoto ni natte iru. - If you’re late, you’re supposed to contact the manager.

It means “it is the rule/arrangement that ~” or “(people) are supposed to ~.” Literally, “it has become a thing (and remains so) that ~,” implying a decision made by a group, company, or some external authority that is currently in effect. It does not sound like a personal decision; it reports an existing rule.

How is 〜ことになっている different from 〜なければならない / 〜ないといけない?

〜ことになっている: Reports an established rule or policy from outside the speaker. Softer, less “command-like.”
〜なければならない / 〜ないといけない: Strong personal obligation, “must/have to,” often felt or imposed by the speaker.
Example:
遅刻したら店長に連絡することになっている = There’s a rule that you’re supposed to contact the manager.
遅刻したら店長に連絡しなければならない = I/you must contact the manager (strong obligation).

How is 〜ことになっている different from 〜ことにしている / 〜ことにする?

〜ことになっている: External rule/decision (company policy, school rule).
〜ことにしている: A personal rule or habit you’ve decided for yourself (“I make a point of ~”).
〜ことにする: You decide (now) to do something.
So 遅刻したら店長に連絡することにしている = I make it my habit to contact the manager if I’m late.

Why does 遅刻したら use past tense した when it’s about the future?

The conditional 〜たら uses the past form before ら, but it doesn’t mean past time here. Vたら means “if/when V happens.” So 遅刻したら = “if/when (you) are late,” even if that lateness is in the future.

Why is it 連絡すること and not just 連絡します?

Because 〜ことになっている needs a noun phrase before it. 連絡すること nominalizes “to contact,” allowing it to be the “thing” that has become the rule. You can’t attach になっている directly to a plain verb; you first turn the action into a noun with こと.

Who is the subject here? Who is supposed to contact the manager?

Japanese often omits the subject. Here it’s understood from context: likely “employees/we/one (people in this workplace).” If you want to be explicit, you can add a topic like うちの店では or 社員は at the start.

Why 店長に and not 店長へ?

With 連絡する, the recipient is most naturally marked by に. へ can appear in some written or formal contexts, but Aに連絡する is the standard, safest choice for “contact A.” So 店長に連絡する is preferred.

What particles go with 連絡する? Can I say 連絡をする?

Recipient: 人に連絡する (店長に連絡する).
Content: 内容を連絡する (予定を連絡する).
Topic: 〜について連絡する (遅刻について連絡する).
Method: 手段で (電話で/LINEで連絡する).
And yes, 連絡する and 連絡をする are both used; 連絡する is a bit crisper.

Does 連絡 specifically mean a phone call?

No. 連絡 is “to contact/communicate” by any channel—call, text, email, chat app, etc. If you want to specify a call, say 電話する / 電話をかける.

Does 遅刻したら mean “after I’m already late”? How do I say “if I’m going to be late (before it happens)”?

In rule statements, 遅刻したら commonly covers the situation broadly, but it can sound like “once you are late.” To clearly mean “if it looks like you will be late,” use:

遅刻しそうになったら
遅刻する場合は
Formal: 遅刻の際は
E.g., 遅刻しそうになったら店長に連絡することになっている。

What’s a more polite or businesslike version of the sentence?

Polite: 遅刻したら店長に連絡することになっています。
More formal/business: 遅刻の際は店長にご連絡いただくことになっております。 (framing the rule addressed to the listener)

How do 〜ことになっている, 〜ことになった, and 〜ことになっていた differ?

〜ことになっている: It is (now) the rule/arrangement.
〜ことになった: It was (just) decided/it has been decided (change or decision point in the past).
〜ことになっていた: It had been arranged/was supposed to be the rule (past state; may imply it didn’t happen as planned).

Can I replace たら with ば or と? What’s the nuance?

遅刻すれば店長に連絡することになっている: Fine; slightly more formal/abstract.
遅刻すると店長に連絡することになっている: Grammatically ok, but と often implies a fixed, automatic result (“whenever X, then Y inevitably”), which can sound a bit mechanistic here. たら is the most natural for this kind of rule.

I’ve seen rules that end with just 〜こと. How is that different from 〜ことになっている?

Ending with 〜こと (e.g., 遅刻したら店長に連絡すること。) is a directive style found in manuals and notices—basically “Do X.” 〜ことになっている reports the existence of such a rule more neutrally: “It is the rule that ~.”

Is ご連絡します correct? What about ご連絡いたします or ご連絡差し上げます?

ご連絡します: Common and acceptable in everyday business speech.
ご連絡いたします: More polite/humble; preferred in formal emails and announcements.
ご連絡差し上げます: Humble and somewhat more formal/literary; still used.
To a superior or customer, ご連絡いたします is a safe, polished choice.

Is 連絡を入れる natural here?

Yes, it’s a very natural colloquial way to say “to drop a message/get in touch.” You could say 遅刻したら店長に連絡を入れることになっている, though in formal writing 連絡する is safer.

Why are there spaces between the words in the example?

They’re likely inserted for learners to see the word boundaries. Standard Japanese writing does not use spaces between words, so you’d normally write it without spaces: 遅刻したら店長に連絡することになっている。

What’s the reading and nuance of 店長?

It’s read てんちょう and means “store/shop manager.” It refers to the person in charge of a shop or branch, not a generic “boss” (上司). In a non-retail company, you’d more likely say 上司 or use the person’s title (e.g., 課長).