8
2.5. Interfaces
2.5.1.
DB15 connector (RS232, audio interface)
It is used for the modem management, data transmission. RS232 exchange protocol, factory setting:
connection speed of 115200 bps, 8-N-1. It is also used for an audio headset connection.
Fig. 2.5.1.
DB15 connector
Table 2.5.1:
DB15 connector pin assignments
Pin
Signal
Direction
Purpose
1
DCD
Modem-PC
indicates presence of DTE to DCE
2
TXD
PC-Modem
data transmission
3
not used
4
MICP
PC-Modem
microphone uncomplemented input and microphone power
supply
5
MICN
PC-Modem
microphone complemented input
6
RXD
Modem-PC
data reception
7
DSR
Modem-PC
data set ready
8
DTR
PC-Modem
data terminal ready
9
GND
Ground
system case
10
SPKP
headphone uncomplemented output
11
CTS
Modem-PC
ready for sending
12
RTS
PC-Modem
request to send
13
RI
Modem-PC
calling indicator
14
RESET
PC-Modem
reset, active low
15
SPKN
Modem-PC
headphone complemented output
Audio headset parameters:
microphone current - 0.5 mA;
microphone power voltage - 100 mA;
loudspeaker impedance - 32 Ohm.
1
5
6
11
10
15
