Specifications

Getting Started
1-26
TDS3000, TDS3000B, and TDS3000C Series Programmer Manual
Table 1- 6: RS-232 troubleshooting (Cont.)
Symptom Possible causes
The oscilloscope RS-232 debug menu
displays CTS: Low, and the oscillo-
scope is using hard flagging.
Verify that the RS-232 cable is the recommended
cable. Some cables may be wired without the CTS or
RTS lines which are used by hard flagging. Verify that
the personal computer program is using CTS/RTS
hard flagging.
After the personal computer program
sends a BREAK, the fi rst message
fails.
Verify that the personal computer program is waiting
for and reading the DCL and end of line terminator
response sent by the oscilloscope.
Comparing GPIB and RS-232
Your system hardware may support both GPIB and RS-232 interfaces. You
should select the interface that best meets your requirements. The GPIB interface
is an eight-bit parallel bus that provides high-speed data transfer and multiple-
instrument control. In contrast, the RS-232 interface is a slower serial data bus
for single instrument control, but is easy to connect to low-cost controllers.
Table 1--7 provides a more in-depth comparison of the GPIB and RS-232
interfaces.
Table 1- 7: Comparison of GPIB and RS-232 interfaces
Operating attribute GPIB RS-232
Cable IEEE-488 Std. 9-wire
Data flow control Hardware, 3-wire handshake Flagging: hard (RTS/CTS)
Data format 8-bit parallel 8-bit serial
Interface control Operator low-level control
message
None
Interface messages Most IEEE-488 Std. Device clear using a break
signal
Interrupts reported Service requests, status and
event code
None, must be polled for
status
Message termination
(Receive)
Hardware EOL, software LF,
or both
Software CR, LF, CRLF, LFCR
Message termination
(Transmit)
Hardware EOL, software LF Software CR, LF, CRLF, LFCR