7500 - Automatic Calling Unit Interface; Table S: Interface Connector Pin Identification - AT&T 7500 User Manual

7500 — Automatic Calling Unit Interface
The multipurpose enhancement option board provides an RS-366 Automatic Calling Unit (ACU)
interface.
The RS-366 ACU interface collects digits until the End of Number (EON) digit is received or until
the expiry of a 3-second inter-digit idle timer.
The leads are listed and defined in the table below.
Table S: Interface Connector Pin Identification
Pin No. Circuit
---
Shield (No Connection)
1
Digit Present
2 DPR
Abandon Call Retry
ACR
3
Call Request
4 CRQ
PND Present Next Digit
5
PWI Power Indication
6
Signal Ground
7 SG
---
Unassigned
8
---
+ Voltage Output for testing
9
---
- Voltage Output for testing
10
---
Unassigned
11
---
Unassigned
12
DSC Distant Station Connected
13
Digit Signal Circuit
14 NB1
Digit Signal Circuit
15 NB2
NB4 Digit Signal Circuit
16
Digit Signal Circuit
17 NB8
---
18 Unassigned
---
Unassigned
19
---
Unassigned
20
---
Unassigned
21
Data Line Occupied
DLO
22
---
Unassigned
23
---
Unassigned
24
---
25 Unassigned
CHAPTER 9: TECHNICAL INFORMATION
Description
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