Pdf User Manuals. View online or download Nec IP4WWTXH-B-TEL(BK) Hardware Manual. Brand: NEC | Category: Telephone System | Size: MB . Please read this manual carefully before operating Check with your NEC Authorized Supplier / System Administrator and make a note of 24 Programmable Function Keys are available for IP4WWTXH-B TEL. When you register a telephone number, the Trunk Access Code should be added in front of the number.