Dokud nebude odečet hotový, nepošlu ho dodavateli.

Dokud means until.

It introduces a time clause that sets the limit for the action in the main clause:

• Dokud nebude odečet hotový, nepošlu ho dodavateli.
• Until the reading is finished, I won’t send it to the supplier.

A very common pattern is:

• dokud + clause
• main clause

But the order can also be reversed:

• Nepošlu ho dodavateli, dokud nebude odečet hotový.

Both are correct.

Because Czech often uses a negative verb after dokud when English uses until with a positive idea.

So:

• dokud nebude hotový = until it is finished / until it becomes ready

The negative expresses that the situation has not happened yet up to that point.

Compare:

• Dokud nebude odečet hotový... = Until the reading is finished...
• literally closer to: As long as the reading is not finished...

This is very normal Czech usage and often feels unusual to English speakers at first.

Because the sentence talks about a future situation.

In English, after until, we usually use the present tense:

• Until it is finished, I won’t send it.

But Czech normally uses the tense that matches the real time reference more directly, so here the subordinate clause is also in the future:

• nebude = will not be

So Czech says:

• Dokud nebude...
  not
• Dokud není... in this context

Odečet can mean different things depending on context, most commonly:

• a reading of a meter, gauge, or instrument
• a reading/result taken from a measuring device
• sometimes a deduction/subtraction in other contexts

In a sentence with dodavateli (to the supplier), the most natural meaning is usually something like a meter reading or a recorded reading that needs to be sent on.

So odečet is a masculine noun, and that affects other words in the sentence.

Because hotový is an adjective agreeing with odečet, which is masculine singular.

• odečet = masculine singular
• therefore: hotový

So:

• odečet je hotový = the reading is finished/ready

By contrast, hotovo is often used more impersonally, like:

• Je hotovo. = It’s done.

That form does not agree with a specific noun in the same way. Here, since the sentence is explicitly about odečet, the agreeing adjective hotový is the natural choice.

Because here hotový is part of the predicate with an implied connection to být:

• odečet nebude hotový

That means will not be finished/ready.

So the structure is:

• noun: odečet
• form of být: nebude
• predicate adjective: hotový

If you say hotový odečet, that sounds more like an attributive phrase inside a noun phrase:

• hotový odečet = a finished/ready reading

But in this sentence, the meaning is clearly predicative: the reading will not be finished yet.

Nepošlu is the 1st person singular future of the perfective verb poslat (to send).

Czech often uses:

• perfective verb for a single completed future action

So:

• pošlu = I will send
• nepošlu = I will not send

This fits well because sending the reading is seen as one complete act.

By contrast, nebudu posílat would use an imperfective verb and would sound more like:

• I won’t be sending
• I won’t send (as an ongoing/repeated action)

In this sentence, nepošlu is the most natural choice.

Ho is the short unstressed pronoun meaning him/it in the accusative.

Here it refers back to odečet:

• odečet = the reading
• pošlu ho = I will send it

Even though English uses it, Czech uses the pronoun form that matches the grammatical gender and case of the noun. Since odečet is masculine singular, ho is the normal short accusative pronoun here.

Because the verb poslat takes:

• something in the accusative
• to someone in the dative

So:

• poslat co? → ho
• poslat komu? → dodavateli

That is why you get:

• pošlu ho dodavateli = I’ll send it to the supplier

The base form is:

• dodavatel = supplier

The dative singular is:

• dodavateli

Because Dokud nebude odečet hotový is a subordinate clause, and Czech separates subordinate clauses from the main clause with a comma.

So the structure is:

• Dokud nebude odečet hotový, = subordinate time clause
• nepošlu ho dodavateli. = main clause

This comma is required in standard Czech spelling.

Yes:

• Nepošlu ho dodavateli, dokud nebude odečet hotový.

This means the same thing.

Starting with Dokud... puts more focus on the time condition first. Starting with Nepošlu... puts more focus on the speaker’s action first.

Both are natural; the difference is mainly one of emphasis and information flow.

Yes, but the nuance is slightly different.

• Dokud nebude odečet hotový, nepošlu ho dodavateli.
  = I won’t send it until the reading is finished.
• Až bude odečet hotový, pošlu ho dodavateli.
  = When/once the reading is finished, I’ll send it to the supplier.

The first version focuses on the limit before which the action will not happen.
The second version focuses on the moment after which the action will happen.

They are closely related, but not identical in viewpoint.