Yes, but... The BSTU cards have a switch on them to be 2000 series or 3000 series so you could keep your phones for the CIX. You could have a mix of 2000 and 3000 phones working on a PSTU2 in the 424, etc.
On the CIX all the phones on a card have to be 2000 series or 3000 series, you can't mix and match on the card, I am pretty sure, not rock solid bet your life that hasn't changed sure. Still, you can use any digital phone but NO electronic phone.
