| Pin | Name | Description | 
| 1 | -- | -- | 
| 2 | DPR | Digit Present--A signal given to the ACE indicating that the digit lines contain a digit | 
| 3 | ACR | Abandon Call and Retry---An indicator signal from the ACE that it could not make a connection. Could be 'busy'. | 
| 4 | CRQ | Call A signal from the DTE that tells the ACE to go 'off hook'Request--- | 
| 5 | PND | Present Next Digit---A signal from the ACE to the DTE to indicate that the ACE is ready to receive the next digit. | 
| 6 | -- | -- | 
| 7 | -- | -- | 
| 8 | -- | -- | 
| 9 | -- | -- | 
| 10 | -- | -- | 
| 11 | -- | -- | 
| 12 | -- | -- | 
| 13 | DSC | Distant Station Connected--Indicator from ACE to DTE that the call is succesfully made. | 
| 14 | NB1-NB8 | Digit Signal Circuits--Four lines containing a parallel BCD dial digit (10 digits, plus control digits) | 
| 15 | NB1-NB8 | Digit Signal Circuits--Four lines containing a parallel BCD dial digit (10 digits, plus control digits) | 
| 16 | NB1-NB8 | Digit Signal Circuits--Four lines containing a parallel BCD dial digit (10 digits, plus control digits) | 
| 17 | NB1-NB8 | Digit Signal Circuits--Four lines containing a parallel BCD dial digit (10 digits, plus control digits) | 
| 18 | -- | -- | 
| 19 | -- | -- | 
| 20 | -- | -- | 
| 21 | -- | -- | 
| 22 | DLO | Data Line Occupied--An indicator that is used by the ACE to let the DTE know that the line it wants to use is used by another device. |