Siemens M20 Terminal Technical Description page 22

Siemens Information and Communication Products
Signal description on the 9-pole D-sub DCE connector:
9-pole D-Sub Description
DCE Pin No
1 DCD
2 RXD
3 TXD
4 DTR
5 GND
6 DSR
7 RTS
8 CTS
9 RI
Signal connection 9-pole D-sub DCE to M20 80-pole SMD connector:
DCE Pin No DCE Signal
1 DCD
2 RXD
3 TXD
4 DTR
5 GND
6 DSR
7 RTS
8 CTS
9 RI
4.3.6 Additional RX/TX interface
This interface is reserved for Siemens development internal purposes.
Signal Function
RXDATA Receive data
TXDATA Transmit data
4.3.7 Voiceband serial ports/digital audio interface (DAI)
To provide a digital audio interface to the user and to offer high-end echo suppression in handsfree environments as an
upgrade feature, the on-board voiceband serial connector between the M20 microcontroller and codec (A/D device) is con-
nected to the 80-pole SMD connector.
Note: the data exchanged on the interface involves 13 bit linear PCM at 8000 samples per second.
Note: in normal cases, the voiceband serial ports (to microcontroller and to codec) have to be interconnected on the PCB
of the base unit.
If using the DAI, connection to the codec-oriented ports is not necessary.
For handsfree applications, see detailed information in Chapter
Signal Function
VSFS_C Synchronisation
VSCLK_C Clock
VSDO_C Data output
VSDI_C Data Input
Version 8 dated 15.03.00
Function
Data Carrier Detect
Receive Data
Transmit Data
Data Terminal Ready
Ground
Data set ready
Request to send
Clear to send
Ring Indication
M20 Signal M20 Pin No
DCD 54
USCTX 72
USCRX 10
DSR 26
DTR 16
USCCTS 9
USCRTS 73
USCRI 11
I/O Level
I 2.8 V
O 2.8 V
I/O Level Comments
I 2.8V to microcontroller (in normal cases, to be connected to VSFS_V)
I 2.8V to microcontroller (in normal cases, to be connected to VSCLK_V)
O 2.8V to microcontroller (in normal cases, to be connected to VSDI_V)
I 2.8V to microcontroller (in normal cases, to be connected to VSDO_V)
CCITT EIA
V-24 RS232
109 CF
104 BB
103 BA
108 CD
102 AB
107 CC
105 CA
106 CB
125 CE
Comments
if unused, connect to signal RES#
may be disconnected if unused
8.8.5 "Adding echo suppression functionality" on page 200
Hardware interfaces
DIN I/O DCE to
66020 DTE
M5 O
D2 O
D1 I
S1 I
E2
M1 O
S2 I
M2 O
M3 O
.
A
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