Page 23 of 101
DWG ID: 181-0101-00A
Date: 2003-09-26
DI1
16
DGND
18
DI2
15
DGND
17
DI3
14
DGND
18
DI4
13
DGND
17
DO1
22
GND
24
DO2
21
GND
23
DO3
20
GND
24
DO4
19
GND
23
AO1
25
GND
29
AO2
26
GND
30
AO3
27
GND
29
AO4
28
GND
30
7.6
Serial I/O Connector (A3J2)
D-sub 9 female. Mate with D-sub 9 male.
Terminal Nr
Description
1
DCD
2
RXD
3
TXD
4
DTR
5
Digital GND
6
DSR
7
RTS
8
CTS
9
RI
8 PACKET RADIO
8.1
Packet Radio Description
AX.25 was developed many years ago as a way of transferring data from one place to
another, through standard types of two-way radio equipment. It is a modification of the
X.25 networking protocol for wired networks.
8.2
Connected vs. Unproto
There are two ways to send data in the AX.25 packet protocol, connected or unproto
(unconnected).
In the CONNECTED mode, a “connection” or link is established between two packet
controllers, over a radio channel. Packets are sent from one controller to another, and
acknowledgments are expected in return that the packets were received correctly. If an