Rev 1.0
1/27/14
22
22
Reference Guide
Interfaces
Refer to the following table for the pin description of the 15-pin serial connector.
Table 8.
Serial Connector Pin Description
Pin #
Signal
I/O
I/O Type
Reset State
Description
1
CT109/DCD
O
+/- 5.5V
Undefined
Data Carrier Detect
2
CT103/TXD
I
+/- 5.5V
Z
Transmit Serial Data
3
Reserved
Do not connect
4
CMIC2P
I
Analog
Microphone positive input
5
CMIC2N
I
Analog
Microphone negative input
6
CT104/RXD
O
+/- 5.5V
1
Receive Serial Data
7
CT107/DSR
O
+/- 5.5V
Z
Data Set Ready
8
CT108-2/DTR
I
+/- 5.5V
Z
Data Terminal Ready
9
GND
GND
Ground
10
CSPK2P
O
Analog
Speaker positive input
11
CT106/CTS
O
+/- 5.5V
Z
Clear To Send
12
CT105/RTS
I
+/- 5.5V
Z
Request To Send
13
CT125/RI
O
+/- 5.5V
Undefined
Ring Indicator
14
RESET
I/O
1V8
Modem Reset
15
CSPK2N
O
Analog
Speaker negative input
3.1.2.1.
RS232 Serial Link Connection
Also known as the main serial link, the RS232 interface performs the voltage level
adaptation (V24/CMOS
⇔
V24/V28) between the internal modem (DCE) and
external applications (DTE).
The signals available on the RS232 serial link are as follows:
•
TX data (CT103/TXD)
•
RX data (CT104/RXD)
•
Request To Send (CT105/RTS)
•
Clear To Send (CT106/CTS)
•
Data Terminal Ready (CT108-2/DTR)
•
Data Set Ready (CT107/DSR)
•
Data Carrier Detect (CT109/DCD)
•
Ring Indicator (CT125/RI)