| Pin
| Function
| Description
| Circuit EIA |
|---|
|
1 | | unused | | |
2 | Digit Present | A signal given to the ACE indicating that the digit lines contain a digit | DPR | |
3 | Abandon Call and Retry | An indicator signal from the ACE that it could not make a connection. Could be "busy". | ACR | |
4 | Call Request | A signal from the DTE that tells the ACE to go "off hook" | CRQ | |
5 | Present Next Digit | A signal from the ACE to the DTE to indicate that the ACE is ready to receive the next digit. | PND | |
6 | | unused | | |
7 | | unused | | |
8 | | unused | | |
9 | | unused | | |
10 | | unused | | |
11 | | unused | | |
12 | | unused | | |
13 | Distant Station Connected | Indicator from ACE to DTE that the call is succesfully made. | DSC | |
14-17 | Digit Signal Circuits | Four lines containing a parallel BCD dial digit (10 digits, plus control digits) | NB1-NB8 | |
18 | | unused | | |
19 | | unused | | |
20 | | unused | | |
21 | | unused | | |
22 | 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. | DLO | |
23 | | unused | | |
24 | | unused | | |
25 | | unused | | |
