25 PIN D-SUB MALE at the DTE (Computer).
25 PIN D-SUB FEMALE at the DCE (Modem).
| 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 |
|
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RSS / РСС
(at the DTE)
(at the DCE)