Technical Reference for ZyXEL omni.net series
D-1
Appendix D
Serial Port Interface
EIA-232D 25 Pin Serial Port Interface
Pin #
Description
ITU-TSS
Signal
Name
EIA
Signal
Name
Signal Description
Signal Direction
DTE - DCE
1 GND
101
AA Protective
Ground
+*
2 TXD
103
BA
Transmitted
Data
*
3 RXD
104
BB
Received
Data
+
4
RTS
105
CA
Request To Send
*
5
CTS
106
CB
Clear To Send
+
6
DSR
107
CC
Data Set Ready
+
7 GND
102
AB Signal
Ground
+*
8
DCD
109
CF
Data Carrier Detected
+
15
Clock Source:
DCE
114
DB
Transmit Clock Signal
+
17
Sync RX Clock
115
DD
Synchronous Receive Clock.
+
18
LA/LBK
141
Local Analog Loopback Test.
*
20 DTR
108/2
108/1
CD
Data Terminal Ready.
Connect DCE to line.
*
21
RD/LBK
140
Remote Digital Loop Test.
*
22 RI 125
CE
Ring
Indicator
+
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
