Phone on the 'Office' line if it's 100% business use. Otherwise it has to go on your 4562 & you have to opt to take a section 179 deduction. Peripherals go either in office or on the 4562 sec. 179, depending on whether they are a 'depreciable item'. Rule of thumb: if it didn't cost over $200, expense it directly instead of on the 4562.