Be online or come online?

[Innocent Fairy]

Which one is correct?

A: ( A friend texting another friend) Hey, come online now. I want to discuss a few things.
B: Hey, be online now. I want to discuss a few things.

[Huda-M]

Which one is correct?

A: ( A friend texting another friend) Hey, come online now. I want to discuss a few things.
B: Hey, be online now. I want to discuss a few things.

Come online :)

[emsr2d2]

Or:

Go online
Get online
Log on
Get on the net

[Innocent Fairy]

Or:

Go online
Get online
Log on
Get on the net

But not be online? What about this sentence which has been taken from MACMILLAN DICTIONARY?

The new plant is expected to be online by September.

[Hedwig]

But not be online? What about this sentence which has been taken from MACMILLAN DICTIONARY?

The new plant is expected to be online by September.

I believe the difference is that "be" is not in the imperative mood here.

H.
-not a teacher-

[emsr2d2]

But not be online? What about this sentence which has been taken from MACMILLAN DICTIONARY?

The new plant is expected to be online by September.

Not in your context, no. If it said "Be online at 7pm and we can chat" then it would be the imperative and would work, but if you're asking someone to log onto the internet immediately, we would not use "Be online".

[Innocent Fairy]

Or:

Go online
Get online
Log on
Get on the net

Can you please show how to use these words/expressions in sentences?

[emsr2d2]

Can you please show how to use these words/expressions in sentences?

Well, they were just suggestions to replace "come/be online" in your original sentence. So:

Hey, go online now. I want to discuss a few things.
Hey, get online now. I want to discuss a few things.
Hey, get on the net now. I want to discuss a few things.
Hey, log on now. I want to discuss a few things.

[Innocent Fairy]

Well, they were just suggestions to replace "come/be online" in your original sentence. So:

Hey, go online now. I want to discuss a few things.
Hey, get online now. I want to discuss a few things.
Hey, get on the net now. I want to discuss a few things.
Hey, log on now. I want to discuss a few things.

Thank you very very much.