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.