Ashley Roll has put together a really nice little unit here. Leave off the
MAX232 and keep these handy for the few times you need true RS232! Plugs
into any 0.1" header to connect to your circuit. Perfect for
the BASIC Stamp or other microcontroller appications.
User comments:
Brady Palmquist says: "James...got your RS232/TTL cable today. FAST! And
it looks great. Will work great for programming radios. Thanks VERY much."
The RLC units can allow you to talk to a wide range of devices, to adjust,
fix, or re-program them.
Monitor ECS Erik Hanson reports that with a little modification, the
RLC-1 can be made into an ECS port converter cable
for data sent by the Sony
DAS
(Digital Alignment Software) to control all aspects of the operation
of the monitor. The RLC-1 must be modified by re-arranging the pins in the
socket to match those on the monitor. The pinout of the connector is, from
top to bottom:
GND (The RLC1 has +5V here, so swap pins 1 and 2)
+5V (The RLC1 has GND here, so swap pins 1 and 2)
Rx
Tx
(The RLC1 Rx and Tx pins are in the correct place aready to send data to
Rx and hear data on Tx on most monitors, but some can be different If you
don't get a connection, try swapping Rx and TX and email us the monitor model)
We now have an ECS specific version of the RLC1 (called the
RLC2) which had the correct pinout and a longer cable.
It's the same other than that; if we are out of stock on RLC1's and you are
in a hurry, order an RLC2 and swap pins 1 and 2.
Network Gear Another use for the RLC is to communicate with onboard
programming or console ports inside Network Switches, Routers, and Storage
systems:
QNAP TS-409 NAS
http://www.cyrius.com/debian/orion/qnap/ts-409/serial.html
documents the connector pinout as follows from left to right looking from
outside toward the center of the board: GND, RX (TX from RLC1), VCC, TX (RX
to RLC1). The connector supplied with the RLC1 must be replaced with a JST
PHR-4^ connector.
Hard Drives The RLC unit can be used to talk to a Seagate 7200.11
hard drive and fix a common problem that causes the drive to get "stuck"
in busy mode.
See http://sites.google.com/site/seagatefix/Home
for detailed instructions. The converter he uses is no longer available (last
we checked) but the RLC does nicely intead.
We benefit if you read this:
RS-232
converters are capable of quite a lot! For instance, another
232
converter can transmit software protocols from your PC to
security cameras that are able to
pan, tilt and zoom.
The RLC-1 RS232 to 3-Volt or 5-Volt (CMOS/TTL) Level converter provides
a simple, low-cost and easy to use solution to interfacing a CMOS or TTL
based circuit to an RS232/EIA232 serial port.
The RLC-1 contains an internal circuit to provide the positive and negative
voltages needed for true RS232/EIA232 compatibility and to convert these
voltages back to logic levels.
It is particularly suited to micro-controller applications; for instance
the PIC or ATMEL families of devices and products using these.
The RLC-1 is built into a small DB9 backshell with a short (10cm or 4") lead
terminating in a standard 0.1" (2.54mm) Molex KK-series 6 pin connector.
The connector is used to provide power to the converter and deliver the Serial
data signals to the attached circuit.
Its small size and convenience make it ideal for prototype or one-off systems,
eliminating the need to design and debug extra level shifting circuits. It
is also useful for circuits that need periodic connection to a host like
dataloggers where a single converter can be used with many products, reducing
the parts count and therefore cost for the individual units.
Connections
Logic Level Pin Assignments
Pin
Color
Signal
Description
1
WHT
Vcc
Power supply to the RLC-1. 3 to 5 Volts.
2
BLK
Gnd
Ground Connection (0V).
3
YEL
Data Out (TX)
Data sent from the logic level device to the RS232 device.
4
RED
Data In (RX)
Data sent from the RS232 device to the logic level device.
5
BLU
RTS
Request to Send signal sent from the RS232 device to the
logic level device to indicate it wishes to transmit data. This signal is
Active Low.
6
GRN
CTS
Clear to Send signal sent from the logic level device to
the RS232 device indicating that it can begin sending data. This signal is
Active Low.
Logic Level Interface
The logic level (CMOS and TTL compatible) interface is a Molex KK Series,
locking and polarised 6 pin crimp terminal housing. A compatible header for
these connectors should be available from most electronics stores, alternatively
a 0.1" (2.54mm) universal header could be used.
Note that the logic level interface is not isolated from the RS232 level
interface and they share a common Ground.
RS232 Interface
The RLC-1 is build into a DB9 Backshell and comes with a female DB9 connector.
The DB9 RS232 connector is wire as a standard "Null Modem"; DTR, DSR and
CD are permanently wired together but the RTS and CTS signals are provided
to the 5-Volt interface and must be connected together if not used in the
attached circuit.
Specifications
Symbol
Parameter
Conditions
Value
Unit
Min
Typ
Max
Isupply
Vcc Power Supply Current
No Load, TA = 25 Deg C
0.3
1
mA
VIL
Logic Level Input Threshold Low
0.8
V
VIH
Logic Level Input Threshold High
2
V
VOL
Logic Level Output Voltage Low
Iout = 1.6mA (to Vcc)
0.4
V
VOH
Logic Level Output Voltage High
Iout = 1mA (to Gnd)
Vcc-0.6
Vcc-0.1
V
DR
Data Rate
300
400
Kbps
Electrical Characteristics:
Vcc = 5V +/-10%, TA = -40 to 85 Deg C, unless otherwise
specified. Typical Values are referred to TA = 25 Deg C.
Absolute Maximum Ratings:
Absolute Maximum Ratings are those values beyond which damage to the device
may occur. Functional operation under these conditions is not to be implied.
Symbol
Parameter
Value
Unit
Notes
Vcc
Unit Power Supply
-0.3 to 6
V
Relative to Ground
VDout
Input Voltage on Data Out Connection
-0.3 to (Vcc +0.3)
V
Relative to Ground
VDin
Output Voltage on Data In Connection
-0.3 to (Vcc +0.3)
V
Relative to Ground
TStore
Storage Temperature Range
-55 to +125
°C
Options Available
Digital Nemesis Pty Ltd makes a single standard unit, but is able to
adapt them as needed. Note that a minimum order quantity will apply for
non-standard configurations. For more information, please contact
STOPspamsalesTakeThisOuT at spamdigitalnemesis.com.
The following are some of the available options: (all units now support 3
Volt as well as 5 Volt operation)
Rugged All Metal Backshell
No Backshell
Bare Leads for Logic Level Interface
Custom Connector for Logic Level Interface
RTS and CTS internally connected and a 4 Pin connector for the Logic Level
Interface
Arthur asks: "Does the RLC invert the Pin-3 data out signal?" James Newton
answers: "Yes, the signal is inverted in terms of electrical polarity.
e.g. a TTL low will generate a positive voltage on the TX output pin, a TTL
high will generate a negative TX. But the other possible correct answer is
No, the signal is not inverted in terms of logic. In the
RS232 standard, a low electrical level
(–3 to –15 volts) is defined as a logic 1, or 'on' or 'high'
and is referred to as 'marking.' So a TTL high which is a positive voltage,
will generate an RS232 "high" which is a negative voltage.
Comments:
"On the page http://www.piclist.com/techref/io/serial/RCL1.htm, it starts
with "RCL" and becomes "RLC" throughout the rest of description. Yep, I know:
Picky, Picky, Picky!!! Thanks for an interesting and useful site."
+James Newton answers: "Oops."
See also:
http://www.awce.com/rs1.htm Kit
with larger components. Does not include a cable. 5 Volt operation only.
As of 2006/08/03 the cost was $10 for the PCB only, $14 for the kit and $26
A&T. If you don't mind the size and want to save $5 in return for building
the kit, this is a good option.
http://www.embedinc.com/products/ser
Larger, no case, no cable, does not convert RTS or DTS, does not support
3.3v. Ss of 2008/02/05 the price is one dollar less up to qty 4, but the
5 unit price is $13.80 which is quite good.
CoolMCU
Converter Cable. Physically larger than the RLC-1. Used to sell
a version that was not a true MAX232, but the current version seems like
a good product. From Canada, so expect shipping and customs delays. Priced
at $16 plus $11 express shipping to US (5 to 7 business days advertised)
for a total price of $27. Compare with our $21 + $6 for 2-4 day Priority
Mail shipping. The price is the same, the shipping is faster. Read the ebay
comments: Many times shipping is fast, but you may be the one that gets held
up in customs. "Product works great, but it took over three weeks for me
to receive it (USA)." kielziz( 5 ) Jun-01-06 08:21 "Works as
described. Shipping is a little slow." asylumboy( 4 ) Jun-01-06 08:10 and
so on. In the end, the same thing costs less in Canada, but more to ship
to the USA. I have offered to resell this product in the USA, but he is
apparently not interested.
Quick, and RELIABLE! RCL-1 RS232 Level Converter in a DB9 backshell only $15.00 Ashley Roll has put together a really nice little unit here. Leave off the MAX232 and keep these handy for the few times you need true RS232!
