User's Guide

User’s Guide SB320 Product Description
2110059 Rev 1.0 Proprietary and Confidential Page 85
The connector pinouts are specified in Table 9-8, and electrical characteristics are specified in
Table 9-9 Serial Interface Electrical Characteristics. Signal types are with respect to the
modem (DCE).
Table 9-8: Host Interface Connector Pinouts
Pin Number Pin Label Type Description
1 \DCD Output Data Carrier Detect
2 RxD Output Receive Data
3 TxD Input Transmit Data
4 \DTR Input Data Terminal Ready
5 GND Ground Ground
6 \DSR Output Data Set Ready
7 \RTS Input Ready To Send
8 \CTS Output Clear To Send
9 \RI Output Ring Indicator
10 \RESET Hardware Reset
11 Reserved Leave unconnected
12 \SHDN Input Graceful modem shutdown.
13 \STATUS_OUT1 Output Power + RF Channel Status
14 \STATUS_OUT2 Output Transmitter
15 \STATUS_OUT3 Output Power Down OK
16 STATUS_IN1 Input
17 STATUS_IN2 Input
18 STATUS_IN3 Input
19 STATUS_IN4 Input
20 – 22 Unused Allowed to float
23 – 24 VBAT Input +5V
25 – 28 GND Ground Ground
29 Unused Allowed to float
30 Reserved Leave unconnected
Table 9-9: Serial Interface Electrical Characteristics
Characteristic Min.(V) Max.(V)
Input Low Voltage -0.3 0.8
Input High Voltage 2.5 5.0
Output High Voltage (Ioh=400 µA) 2.4 –
Output Low Voltage (Iol=3.2 mA) – 0.5
Serial Port Interface
The serial port pins comprise a standard set of serial data and handshaking lines. All signals are
negative assertion, HCMOS logic compatible. These signals must be terminated properly if they
are not used. Unused input signals must be pulled to the appropriate in-active state through a
resistor (10k). Unused output signals may be left unterminated. If a signal may have use as an
input or an output (I/O) then treat it as an input for termination purposes.
Hardware handshaking should be enabled using \CTS and \RTS as the primary flow control
signals. The remaining handshaking lines (\DCD, \DTR, \DSR, and \RI) are, strictly speaking, not
needed; however they are desirable for TCP/IP stack usage and are supported for any applications
that may require them.