CMU Hardware Interfaces 
1100.4903.12 8.7  E-8 
Table 8-3   Transmission parameters of the RS-232 interface 
Parameter  Default  Description / Parameter Range 
Baud rate 
9600 baud
1
 
The instrument allows baud rates between 110 and 115200 baud to be set,  
see chapter 4, Setup - Remote menu. 
Data bits  8  Data transmission is in the 7- or 8-bit ASCII code, starting with the least significant bit 
(LSB).  
Start bit  1  Each data byte begins with a start bit. The falling edge of the start bit indicates the 
beginning of the data byte. 
Parity bit  None  A parity bit can be transmitted for error protection. The settings No parity, even or 
odd parity are allowed.  
Stop bit  1  Transmission of a data byte is terminated by one or two stop bits. The sum of data 
bits and stop bits must be equal to 9. 
 
Example:  Transmission of character 'A' (41 Hex) in 8-bit ASCII code with even parity and one  
 stop bit: 
 01  02  03  04  05  06  07  08  09  10  11 
  Bit 01 = 
Start bit 
Bit 02...09 = Data bits  Bit 10 = 
Parity bit
Bit 11 =
Stop bit 
 
 
Interface functions 
For interface control, some control characters from the ASCII code range of 0 to 20 hex are predefined 
and can be transmitted via the interface. 
 
Table 8-4   Control strings or control characters of the RS-232-C interface 
Control Character  Function 
Break (at least 1 character only log 0)  Reset instrument 
0Dhex, 0Ahex  Terminator <CR>, <LF> 
Switchover between local/remote 
 
 
 
  
 
1
 The default baud rate is 19200 baud for COM ports that are used as GPIB connectors.