
26
LD485A-HS and LD485A-HS Opto-Isolated
Table 3. RS-232 Interface (continued)
(* Denotes pins that are used)
Pin
Circuit
Description
Signal Type
Direction
14
SBA
Secondary Transmit
Data
To DCE
Data
15
DB
Transmit Signal
Timing
From DCE
Element Timing (DCE)
16
SBB
Secondary Receive
Data
From DCE
Data
17
DD
Receiver Signal
Timing
From DCE
Element Timing
18
—
Local Loopback
Test
To DCE
19
SCA
Secondary Request
Control
To DCE
To Send
20*
CD
Data Terminal Ready
Control
To DCE
21
CG
Signal Quality
Control
From DCE
Detector
22
CE
Ring Indicator
Control
From DCE