As stated in my post above, the Radio Shack part no. 274-1567 fits the Airtronics transmitter. Also as stated above, it is 5mm OD and 2.1mm ID. I do not know where the included quote picked up the dimensions quoted here but it was not what was stated above. Incidently, if you have a Hitec transmitter charger, it will fit and function perfectly with the RDS8000 transmitter. If you replace the connector on the Futaba charger with the 274-1567 connector it will also work .
ORIGINAL: EloyM
CORRECTION!!!!! You can NOT charge an Airtronics transmitter with the same charger or harness as you do all others. JR with its opposite polarity is of course completely out of the loop.. The difference is not electronic, but mechanical..........
The charge connector most used has an internal pin of 2.5mm - NOT 3.5 as stated. Airtronics uses a smaller one with a 2.1 pin. The larger one will go in, but will not make a dependable solid contact.