CHAPTER 6: RS-232 Interface Pinning
15
Table 6-1. RS-232 Interface Pinning (continued)
PIN
CIRCUIT
DESCRIPTION
SIGNAL TYPE
DIRECTION
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
23
CH
Data Signal Rate
Control
To DCE
Selector (DTE)
or
CI
Data Signal Rate
Control
From DCE
Selector (DCE)
24
DA
Transmitter Signal
Timing
To DCE
Element Timing (DTE)
25
—
Test Mode/No Signal
—
—
