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a
Circuit 108/2
Data terminal ready
DTE->DCE
ITU-T name: DTR
RS232C
name:CD
Pin no.:20
State ON:
DTE is ready for data transmission
State OFF:
DTE cannot transfer data. The modem is prevented
from connecting to the line, and existing connections will be
broken.
109
Data carrier detect
DTE<-DCE
ITU-T name: DCD RS232C name:CF
Pin no.:8
State ON:
'The received signal level is not sufficient for data
transmission.
State OFF:
Data transmission is not possible.
The modem
does not receive any carrier, or the signal level of the carrier is
too low.
111.
Data Rate Select
DTE->DCE
ITU-T name: DRS RS232C
name:C!
Pin. no.:23
State ON: — High data rate is selected.
State OFF:
Low data rate is selected.
112
Data Rate Indicator (Not supported)
DTE<-DCE
ITU-T name: DRS
RS232C name:CH
Pin. no.:12
State ON:
The modem operates with high data rate
State OFF:
The modem operates with low data rate
113.
Transmitter signal element timing
DTE->DCE
ITU-T name: XCK RS232C name:DA
Pin no.:24
During synchronous transmission, the transmission timing is
either controlled bye DTE through circuit 113, or by DCE through
circuit 114.
When using external control (113), DTE has to
generate timing signals in the form of a 50% duty cycle square
wave signal with a frequency of 1200/600 Hz, 0.01%
synchronised with transmitted data. OFF to ON transition will
normally indicate the centre of each signal element on circuit
103 (TXD). See figure below, Circuit 115.
114
Transm. signal element timing
DTE<-DCE
ITU-T name: TCK
RS232C name:DB
Pin no.:15
DCE will determine transmitter timing through circuit 114.
OFF
to ON transitions will normally indicate the centre of each signal
element on circuit 103 (TXD). See figure below, Circuit 115.
LZTR104006 R1.00
1 5-3
Zat14.4/14.4-7 and 19.2/19.2-7
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