Product Overview; Getting Started - B+B SmartWorx 232OTTL Quick Start Manual

Product Overview

1,500 V
Optical Isolation
RS-232
DB25 Female
232TTL SPECIFICATIONS
4 channels, TD, RD, RTS, CTS.
RS-232 side pinned out as DCE.
TTL/CMOS compatible voltage levels
Signals
(low < 0.8V, high > 2.0V).
Inverted outputs (non-inverted available
with modification).
Baud Rate 38.4 kbps
Port-powered by TD, DTR, and RTS
Power (requires two lines in any state).
RS-232 Side OR +12 to 16 VDC at 30 mA maximum
on pins 25 and 12.
+12 to 16 VDC at 25 mA maximum on
Power
power jack OR pins 25 and 12
TTL Side
(+5 VDC available with modification)
Temperature 0 to 70°C
1

Getting Started

The 232OTTL is an RS-232 to TTL converter with 1500V
isolation. Channels TD and RTS convert RS-232 to 0-5V
TTL signals and channels RD and CTS convert 0-5V TTL
signals to RS-232. The RS-232 side has a DB25 female
connector pinned out to plug directly into the COM port of
a computer or any other DTE device. The TTL side has a
DB25 male connector.
2
Signal Lines
The 232OTTL supports 4 signal lines and Ground as
shown in Figure 1. Two of these four lines, TD and RTS,
convert RS-232 inputs to TTL outputs. The other two
lines, RD and CTS, convert TTL inputs to RS-232 outputs.
These lines communicate at baud rates up to 38.4 kbps.
TTL
DB25 Male Port
(5V)
It is important that only TTL logic (0 to +5V) is used
for the TTL side of the converter.
The maximum sinking current for one TTL output is 8
mA. The maximum source current for one TTL is 0.8 mA.
Signal levels are inverted by the converter in its standard
configuration as shown in Table 1. See "Options Requiring
Modification" section if non-inverted outputs are desired.
TTL INPUT
High (>2.0V)
Low (<0.8V)
TTL OUTPUT
High (>2.0V)
Low (<0.8V)
Figure 1. Signal Lines Diagram
RS-232 OUTPUT
-5V maximum, -9V typical
+5V maximum, +9V typical
RS-232 INPUT
-5V maximum, -9V typical
+5V maximum, +9V typical
Table 1. Standard Inverted Outputs
3
Power
The RS-232 side of the 232OTTL derives its power from the
outputs of the host RS-232 port. TD, RTS, and DTR lines
may be used to port power the RS-232 side. A minimum
of two of these lines in either high or low states is required
for proper operation. If your port meets the low voltage
requirements of RS-562, you will need to externally power
the RS-232 side of the 232OTTL. An RS-562 port, typically
found on handheld computers, will only produce about
3.7 volts, which is not adequate to power the isolator. To
externally power the RS-232 side, connect the positive lead
of the +12VDC power supply to pin 25 and the GND lead to
pin 12 of the DB25 female connector.
The TTL side of the 232OTTL requires a power supply to
operate. +12VDC may be connected to the power jack on
the side of the unit, or on pins 25 (+12VDC) and 12(GND) of
the DB25 male connector. See the section titled "Options
Requiring Modification" if it is necessary to power the TTL
side from a +5V supply.
4
Options Requiring Modification
The 232OTTL may be modified to non-inverted signals as
shown in Table 2 by placing a jumper wire across JP1:A
labeled "NI".
TTL INPUT RS-232 OUTPUT
High (>2.0V) +5V maximum, +9V typical
Low (<0.8V) -5V maximum, -9V typical
TTL OUTPUT RS-232 INPUT
High (>2.0V) +5V maximum, +9V typical
Low (<0.8V) -5V maximum, -9V typical
Table 2. Modified to Non-Inverted Outputs
The 232OTTL may also be modified to accept a +5V
supply on the TTL side. Remove the 0 ohm surface mount
resistor labeled R13 and place a jumper wire across JP1:B
labeled +5V. A +4.75 to +5.25V at a maximum of 25mA is
necessary to power the TTL side of the converter when this
modification is made.
For assistance with these modifications, or to have the
232OTTL modified before shipment, call B+B SmartWorx.