RS232 Adapters

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A small RS232 adapter using a Max233 (or equivalent) IC. Use for connecting micro controllers to PCs or other terminals.

Small Adapter! Only 1.2” X 1.2”

Eliminates having to place a Max232 or Max233 on every development or production board. One end (DB9) connects to  a PC or any other terminal. The other end provides a 4-pin header to connect to any micro controller board that requires serial I/O. The micro controller board provides the adapter with it operating  voltage (3.3 to 5 volts*). An LED can be installed to show when power is supplied. Provision is made for a line filtering capacitor, should a long 4 wire connector be used. The Max233 is a dual  transciever and has internal capacitors, therefore requiring no external parts. Available as a  kit or bare pcb in the BenchParts section.

* With a  3.3v supply the AD233 provides an RS232 voltage swing form -6v to +6v which is sufficient for most RS232 applications. At 5v it provides -10v to +10v, therefore, it may not work properly in some 3.3v applications.

PCB Layout

Serial DB9 to PC

The Max233 adapter is available in the Parts section. It can be purchased as a complete kit or just the bare pcb.

4 Pin header to connect Tx, Rx, Ground and 5v supply

1.2”

1.2”

PCB

Shown assembled, can be purchased as a kit or just the bare pcb. Model AD233AK $19.00

How to order

Max233 RS232 Schematic (Model AK)

* With a  3.3v supply the AD233 provides an RS232 voltage swing form -6v to +6v which is sufficient for most RS232 applications. At 5v it provides -10v to +10v, therefore, it may not work properly in some 3.3v applications.

Bare PCB

AD233BK with CTS/RTS pinouts

Model AD233BK - $20.00

Same as the popular AD233AK except that it includes the CTS/RTS handshake pinouts from the DB9 connector via the Max233. The CTS/RTS pins can be jumpered if handshaking is not required

How to order

PCB layout

RS232 (A)

3 - 5v supply

New! Dual RS232 Adapter

RS232 (B)

TTL  (A) RX-TX   (B) RX-TX

How to order

AD233DK (on left) Similar to the AD233AK except that it has a second I/O port. Designed for microcontroller projects that require two RS232 I/Os. For example one port can be used to collect data from a device such as a GPS and the other port can be connected to a PC terminal to monitor or control the device. Uses a Max233 (or equiv) IC and requires a 3 to 5v dc supply*.

AD233DK complete kit $23.00

AD233DPCB bare printed circuit board

* With a  3.3v supply the AD233 provides an RS232 voltage swing form -6v to +6v which is sufficient for most RS232 applications. At 5v it provides -10v to +10v,  therefore, it may not work properly in some 3.3v applications.

A232DB Max232 adapter Rev4

Top side of pcb

Bottom side of pcb

Shown assembled

A232DBA - Assembled $18 without hood

A232DBH - Assembled with /Hood kit   $20.00

A232DBK - Kit of all parts $13.00  without hood

Above are 5 volt version

Tiny pcb approx 0.55 x 0.61 inches! Ideal for those projects that require an affordable RS232 I/O port. The kit Includes an SOIC Max232, four 1uf SMD tantalum capacitors, pcb and a DB9F connector. It accepts any TTL RS232 Rx/Tx signals. Requires 5volts DC. This pcb was originally designed for a custom DB9 shell which was a couple of mm larger than most DB9 hoods found in electronic stores. One could most probably make it fit in a standard hood by shaving the corners and edges.

Pcb layout

Max232 pins

5v version uses an IC232 and 1uf caps and the 3v version uses an IC3232 and 0.1uf caps.

3.3v RS232 module

Assembly document

Shown mounted in a DB9 hood

Ordering

The AD232DBH is also available as a 3.3 volt unit. If you would like the 3.3v version please order part number A232DBH3v.

a232ct_assm02

A232DBCT (5v or 3.3v)

New! A232DBCT same as the above but it includes the CTS/RTS lines. Available as a 5v module ( A232DBHCT ) or a 3.3v module (A232DBHCT3V). The modules include a plastic DB9 hood kit. Pinouts on the board are V+,GND,CTS,RTS, TX and RX

Ordering....

A232DBCT  (5v ver)  - Assembled with /Hood kit   $20.00

A232DBCT3V (3.3v ver) - Assembled with /Hood kit   $20.00

st232_assm2w

ST232A  3.3v TTL to RS232 adapter module has a 3.5MM stereo jack which provides three lines, Gnd,Tx and Rx. The board provides jumpers to configure the jack’s Tip and Ring as Tx or Rx. It comes as assembled or as a kit. Will work on 3.3v to 5v.(Email if you would like the 5v-7v version)

str232pcbloutw
str232assm1w

ST232A Assembled module $20.00

ST232K module kit $15.00

Documentation

Pcb layout

rj45assmw

RJ45SA  3.3v TTL to RS232 adapter with an RJ45 jack. It provides connections for Tx,Rx,Cts and Rts. The pin connections on the RJ45 are Lantronix compatible. It comes as assembled or as a kit. It will work on 3.3v to 5v. (Email if you would like the 5v-7v version)

r45
rj45layoutw

RJ45SA Assembled module $20.00

RJ45SK module kit $15.00

Documentation

Note: This adapter can also be provided as a strip of 2,3 or 4 modules. E-mail if interested.

Pcb layout

A232DTE TTL to RS232 DTE with male DB9 connector

assm2w

A232DTE  3.3v TTL to RS232 adapter configured as a DTE adapter with a male DB9 connector. It comes as assembled or as a kit. It will work on 3.3v to 5v.(Email if you would like the 5v-7v version)

DB9malew

Male DB9 pins

Order

A232DTE Assembled module $20.00

A232DTEK  module kit $15.00

Documentation

A232DBLassmw

A232DBL  3.3v or 5v*  Dual TTL to RS232 adapter board. Designed for engineers/hobbyists who need an adapter without a DB9 connector so that they can wire their own. The board provides two separate TTL to RS232 I/O channels, each has Tx, Rx and Gnd lines. The adapter is available as a kit or assembled. Documentation

Order

A232DBL3V 3.3v adapter assembled $18

A232DBLK3V 3.3v adapter kit $14

*If you would like the 5v version please indicate in the comment section when ordering.

RS232 7-14 vdc supply modules

AD231_12vassmw

AD231_12V An RS232 adapter with an on-board voltage regulator, protection diode and an LED indicator. The adapter can be configured with or without  CTS/RTS handshake lines. It will run off a 7 to 14 vdc power supply and can provide a -12v to +12v RS232 line signals with a 12vdc supply. Sold as a kit and requires soldering.

Order AD231V12K $22.00

Documentation

AD233_12Vassmw

AD233_12V An RS232 adapter with an on-board voltage regulator, protection diode and an LED indicator. The adapter can be configured with or without  CTS/RTS handshake lines. It will run off a 7 to 14 vdc power supply and provides a -10v to +10v RS232 line signal. Sold as a kit and requires soldering

Order AD233V12K $22.00

Documentation

 For those projects that require multiple serial RS232 I/O ports. Features a very small adapter with four independent serial RS232 ports (DB9 female connectors). The adapter can can be powered by an on-board 5v regulator or by the host’s 5v supply (jumper selectable). All I/O pins, including the power lines, are brought to a 5x2 standard 0.1” spaced header. The kit mainly comprises of  surface mount parts, such as the two IC232s, capacitors and resistor.

Shown assembled

Assembly of this kit requires that the user has the necessary tools and skills to work with SMD (surface mount device) components

$36.00 complete kit

Ordering

Assembly document

PCB layout

AD232SP shown assembled

RS232 adapter with an on-board regulator which can, if possible,  use the DTE ‘s (such as a PC) RTS/DTR  voltage to power the Max232 IC. The RTS/DTR lines are protected with fast switching diodes. An external power supply can be used if the DTE device cannot provide sufficient power on the RTS/DTR lines. Jumper selectable. Pinouts for CTS,RX,TX, GND , plus for an external supply, if required. Includes an LED to indicate power supply. The kit mainly consists of surface mount parts. Simple to use. Connect your projects’ TTL RX/Tx  lines to the AD232SP and run a common ground wire between the two. When the DTE, (such as a computer with a serial port) opens a terminal application,  the AD232SP will become active and the power LED will light up.    Requires Assembly

AD232SP $23.00 complete kit or $10.00 for the pcb only AD232SPCB

Ordering

Shown assembled

A small RS232 adapter with handshaking options. Jumper configurable. Can be configured as a null modem with no handshking, or with DSR/DTR handshaking or with CTS/RTS handshaking. It provides Rx/Tx pins and 2 control pins for either DSR/DTR or CTS/RTS handshake signals. The kit uses all surface mount parts and requires assembly. The IC is a Max232 SOIC16. The board has a power LED indicator and requires 5v for operation. It has a standard DB9 female RS232 connector. Provisions are made for an optional  reverse voltage protection diode can be used. Comes as a kit and requires assembly and soldering of all smd parts.

Documentation

Jumper Settings

Null modem (no handshake)  1-2 and 5-6,  CTS/RTS handshake  3-5 and 4-6, DTR/DSR handshake 1-3 and 2-4

Ordering

If a 3v version is required, please request by email

A232C $19.00 complete kit or $10.00 for the pcb only A232CB

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Updated on:

January 29, 2014 

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