Insys Modem 56k small INT 2.0 11-02-01-01-43.003 Manuale Utente

INSYS Modem 56k small INT 2.0/USB 1.0 

Functions 

June 06 

23 

 
Hardware data flow control with the application (RTS): 
 

 

Modem

 

RS232 Cable 

 

RTS Line 

Application 

(E.g.: PC or con-

trol) 

The application sets the RTS line to OFF to request from the mo-

dem to interrupt the data transmission. 

It will depend on the according application software if the RTS/CTS 
lines can be operated. 

The application sets the RTS line to ON to request data from the 
modem. 

 

Modem 

 

Send data 

XON or XOFF character 

Application 
(E.g.: PC or 

control) 

When the input buffer of the modem exceeds a certain fill state, the 
modem will insert an XOFF character into the data stream to the ap-
plication. This character will cause the application to send no more 
data. 

It will depend on the according application software if the RTS/CTS 
data flow control is supported. 

After the modem has processed the input buffer so far, it will insert a 
XON character into the data stream. This character will cause the 
application to send data to the modem again. Analogously, the ap-
plicaiton can control the data stream from the modem to the appli-
cation.

 

The XON/XOFF method is only available when the transmitted data 
do not contain the characters XON or XOFF, which usually appear 
only in actual ASCII texts (7 bit). When binary data (programs, …) are 
transmitted,  also for BTX operation or in the XMODEM transmission 
protocol, for example, occasionally appearing XON or XOFF charac-
ters would disturb the operation. 

AT&R 

AT&K4