"Hello, can you hear me?"

Translation: Allô, est-ce que vous m'entendez ?

[spielzebub]

Surely this is "do you hear me" rather than "can you hear me"?

[Sitesurf]

Both are valid and equally accepted.

[Gordon964264]

why not "peux-tu m'entendre"?

[Sitesurf]

It is possible, but be aware that it is not the most common way of saying this. In French, the verb "pouvoir" is not used in such situations: "m'entendez-vous / m'entends-tu ?"

[jdaneau87]

'Salut, est-ce que tu m'entends?' was not accepted