Teledesign Systems Inc TS4000EH Manuel D’Utilisation

Serial port 1 can be configured for either RS-232 or TTL signal levels.  The signal 
level selection is controlled with internal jumper plugs (see Appendix F - Internal 
Jumper Block). 
 
 
The RS-232 standard defines minimum and maximum voltage levels for the 
drivers and receivers.  However, in practice the drivers and receivers work 
correctly with signal levels that are different from the specification. 

 

 
 

Drivers (into a 3k to 7k ohm load)                 

RS-232 Specification                                      
Actual TS4000 Drive Levels 

                      
-15 to -5         
-9 to -6 

                    
+5 to +15      
+6 to +9 

Receivers (with 3k to 7k ohm load)                       

RS-232 Specification                                      
Actual TS4000 Receive Levels 

                      
-25 to -3         
-25 to +0.8 

                    
+3 to +25       
+2.4 to +25 

 
 
 

Output (Driver)  

0.0 to +0.4                  
(sinking up to 4 mA) 

+3.0 to +5.0 
(sourcing up to 4 mA) 

Input (Receiver)  

-25 to +0.8 

+2.4 to +25 

 

(3k to 7k ohm load) 

 
 
The signal polarity is the same for both RS-232 and TTL operation. 
 
Level State 
Voltage Low 

Mark 
Control signal inactive 
Stop bit state (end of async character) 
Logic one data bit state (within async character) 
 

Voltage High 

Space 
Control signal active 
Start bit state (beginning of async character) 
Logic zero data bit state (within async character)