Tektronix 2221 - Page 154

Appendix B - 2221 Operators
u
INTERCONNECTION RULES
There are several simple rules that satisfy most
RS -
232
- C
interconnections
requirements .
3. A “ Gender Changer " has straight - through connec
tions that may be used to convert a non - standard port
connector ( a DTE device with a female connector or a
DCE device with a male connector ) for connection with a
standard RS - 232 - C cable . Gender changers come as
male - to - male
and female - to
- female . The
male - to - male
changer
is
the
most
used
.
1. A standard RS - 232 - C cable connects a DTE device
to a DCE device . Both devices must adhere to the electri
cal and mechanical specifications of the RS - 232 - C stan
dard . The standard cable has a female connector on one
end and a male connector on the other end . The Transmit
and Receive conductors are not interchanged . The stan
dard RS - 232 - C cable is sometimes referred to as a
" straight through " cable . In Table B - 1 , the Cable - Type
Identification table , the straight - through cable is referred to
as
Type A.
The
gender
changer is
connected
between
the
non
conforming
device
and the
appropriate
end of
a
standard
RS - 232 - C cable
. Situations
may occur when
neither device
has
conforming connectors
; in that
case , use
gender
changers
on
both
devices to
permit
interconnection
with
a
standard RS - 232 - C cable ( or use one of the specified
cables
from
Table
B - 1
) .
4. If non - standard cabling or connectors are used , an
interconnection terminal box may be needed to provide
user - customized hookups .
2. A " Null
Modem " cable
or device may
be used to
interconnect two DTE or two DCE devices . Generally the
cable is custom made with RS - 232 - C connectors that
match the devices to be interconnected . A null modem
cable permits two devices of the same type ( DCE to DCE
and DTE to
DTE ) to
communicate as if they
were
con
nected DTE to DCE . The Transmit and Receive lines and
the associated handshake line are swapped in the null
modem to satisfy the requirements for data transfer
between the two devices . See Figure B - 1 for the “ Null
Modem "
cable
wiring
schematic .
The 2200 Family DSOs have both a DTE port and a
DCE port to
make it
easy to
connect to either
a DTE
or a
DCE device using
a
standard RS - 232 - C cable
. Both con
nectors conform to
the electrical
and
mechanical
specifications
of the RS - 232
- C . Therefore
, in most cases
,
you
should not have
to
modify the 2200
Family
DSO end
of an
interconnection cable to
hook up other
devices with
the
oscilloscope .
بال
RS - 232 - C
DTE
DEVICE 1
RS -
232
- C
OTE DEVICE 2
PIN
PIN
1
1
2
3
2
3
1
4
♡
on
von
AWNA
5
6
7
6
7
8
u
20
6530-18
U
Figure 8-1 .
Null Modem cable
wiring .
B - 2
u