Tektronix SDA601, Service Manual

Page: 27 / 132

Operating Information
SDA 601 Serial Digital Analyzer 2- 5
straight-through—a simple ribbon cable may be adequate. Use a null modem
cable (which swaps the lines between pins 2 and 3 and pins 7 and 8) to commu-
nicate with another DCE device. Figures 2--3 and 2--4 illustrate cable wiring for
communicating with a device that has a 25-pin serial connector.
Because of space limitations on the connector end of the SDA601, you may
have to insert a 9-pin adapter between the cable and the connector. If the cable
has a female end, use a male/male adapter such as ITT Cannon p/n 111805--1.
Table 2- 1: RS-232 Connector Pin Assignments
764 DB9 Pin Signal Name Signal Direction
1 Not connected —
2 RXD (Received Data) From SDA601
3 TXD (Transmitted Data) To SDA601
4 Not connected —
5 Signal Ground —
6 Not connected —
7 RTS (Request to Send) To SDA601
8 CTS (Clear to Send) From SDA601
9 Not connected —
NOTE
. RS-232 signals are named from the perspective of the DTE device. Since
the SDA601 is a DCE device, pin 2 (“Received Data”) is an
output
from the
instrument; that is, the data is received by the connected DTE device.
Figure 2- 3: Connecting to a DTE Device with a DB25 Serial Port