אנגלית ⇄ סינית צרפתית רוסית +

central office code מתח
.תקשור	внутризоновый код; код центральной АТС
	индекс АТС (The exchange code or central office code (often called the prefix by the public) refers to the first three digits of the local number (NXX), though most non-rural exchanges have more than one code or prefix. wiki Alexander Demidov)