RLC-2: RS232 Level Converter for ECS in a DB9 backshell
Disclamers
*WARNING* CRT Monitors have a case for a reason: The circuitry inside
produces VERY high voltages which will KILL YOU DEAD if you don't know what
you are doing. If you have to open the case to get to the ECS port on your
monitor... don't.
We don't know anything about repairing monitors or about the DAS software.
We are just supplying a cable, built to the specifications provided on the
forum.
Cable
The RLC-2 is the ECS version of the RLC-1. The RLC-1
can be turned into an ECS converter just by swapping pins 1 and 2 in the
connector. The RLC-2 has a longer cable and the pins on the TTL end of the
RLC-2 are already correct for the ECS port. The pinout of the connector on
the RLC-2 is, from top to
bottom^:
GND (connects to GND on the Monitors ECS port)
+5V (connects to STBY +5VDC on the Monitors ECS port)
Tx (connects to the RX pin on the Monitors ECS port)
Rx (connects to the TX pin on the Monitors ECS port)
The RLC-2 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-2 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-2 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
BLK
Gnd
Ground Connection (0V).
2
WHT
Vcc
Power supply to the RLC-1. 3 to 5 Volts.
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-2 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
Custom versions of this cable can be manufactured as needed. Note that
a minimum order quantity will apply for non-standard configurations. For
more information, please contact us.
The following are some of the available options: (all units now support 3
Volt as well as 5 Volt operation)
No Backshell
LED indicator lights for RX, TX, RTS and CTS.
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
See also:
http://www.awce.com/rs1.htm Kit
with larger components. Does not include a cable, wrong pinout for ECS. 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, wrong pinout for ECS, does not convert RTS or
DTS, does not support 3.3v. As 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.
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!
