except at the firing point prior to firing.

[shana15]

Доброе утро! Помогите перевести "...except at the firing point prior to firing"

Hand held radios and telephones are not to be operated within 15 m of an
electric detonator (outside the metal container) or a completed firing circuit,
except at the firing point prior to firing.

[october]

по-русски prior to firing, Hand held radios and .....
т.е перед подрывом не допускается(запрещается, не разрешается) работа.....