Tektronix 2230

Options and Accessories-2230 Operators
NOTE
Do not hook up external devices to both the DTE
connector and the DCE connector at the same time.
RS-232-C DCE Connector-Provides a connector that
meets the EIA RS-232-2 standard for data communica-
tions equipment (see Figure 7-3). Table 7-10 lists the
function of each pin of the connector. The connector is
provided only on Option 12 instruments.
Option 12 Interface Status Indicators
The three indicator labels (SRQ, ADDR, and PLOT)
above the CRT indicate the status of the Communications
interface. Refer to Figure 7-2 (shown previously) for the
location of the status indicators. Their operation is
as follows:
The SRQ indicator is on only during the time an asyn-
chronous status byte is being sent. A status byte or
event code is not generated for power-on. Events
must be queried to receive pending events codes.
Status must also be queried to receive pending status
bytes, except for command and execution error status
which are returned immediately upon recognition of an
Pin
1
2a
3a
4
5
6
7a
8
20
Table 7-10
RS-232-C DCE Connector
Signal Name
Function
Internal
External
CHAS CHAS
Chassis ground
GND
GND
IRXD TXD
Transmitted data
ITXD
RXC Received data
ICTS
RTS Request to send
IRTS CTS
Clear to send
IDTR DSR
Data set ready
SIG SIG
Signal ground
GND GND
IRLSDC1
RLSD Received line signal detect
IDSR DTR
Data terminal ready
8
These lines are all that are required for communication
without hard control lines.
7-12
error. If OPC is also on, additional system events (i.e.,
warnings and operation complete) will also generate an
asynchronous service request. All status bytes are
prevented from reporting if RQS is off, but the SRQ
indicator does not indicate that a status byte is pend-
ing. In this case, the event code must be queried
(EVEnt?) to find out if an event has happened.
The ADDR indicator is on when a carrier is detected.
With no devices connected to either the DTE port or
the DCE port, the ADDR indicator will be on. If an
RS-232-C DCE device is connected to the DCE port,
the carrier will also be on all the time. The indicator will
be off if a DTE device is connected to the DTE port
and no carrier is detected.
The PLOT indicator is on when the communication
option is currently sending waveform data. Acquisitions
are inhibited during this time.
RS-232-C Parameter Selection
Selection of RS-232-C parameters (baud rate, parity,
and line terminator) must be made prior to power on using
the RS-232-C PARAMETER switch and Table 7-11
through Table 7-13. Changes to the PARAMETER switch
after power on will not be read until the next power on
occurs. PARAMETERS switch settings and setups for
some common printers and plotters are given in Appendix
B. There are two other communications parameters that
are set using commands via the interface itself. These are
STOP bits and FLOW control. The most used setting for
STOP is 1. The power-on default for FLOW is OFF.
Baud Rate. Baud rate switch settings determine the
baud rate used by the instrument for both sending and
receiving data. The available baud rates are listed in
Table 7-12.
When OFF LINE (baud-rate switch settings 1111) is
selected, the instrument still presents an active load to the
other RS-232-C device, but it can't send or receive any
interface traffic.
Use Table 7-11, Table 7-12, and the PARAMETERS
switch to select the desired baud rate.
Parity. The selected parity settings determine the
oscilloscope's response to received parity errors and the
parity of data sent by the oscilloscope.
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