The TM-D1000 has a non-standard word clock input curcuit that can damage word clock output of the original 2408. This damage will only occur if you turn on the 2408 with the TM-D1000 turned off. We do have a modification available to prevent damage to the 2408 word clock connection. This modification is not covered under warranty. The charge for the modification is $49.95 and can be arranged by contacting Technical Support. Please note that the 2408 MK II does not require this modification.