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RLC-2: RS232 Level Converter for ECS in a DB9 backshell

The RLC-2 converts electronic signal levels between true RS232 levels at computer serial ports and standard TTL (5v or 3.3v) levels commonly found in microcontroller or other related logic devices. It is based on a standard level converter chip, commonly available, but it squeezes that chip and its supporting components into a very small space so that they actually fit in the backshell of a standard DB9 connector! This provides a rugged enclosure for reliable operation.

E.C.S. Monitor Ports

Along with many other uses, this cable can be used to connect your PC to the ECS port (on the back, near the right side, under a small pop out plug ^^) in your Sony (Dell, etc... any made by Sony) monitor so that all the settings stored in the monitors EEPROM can be read out and adjusted by Sony DAS software. This includes the FULL range of color / geometry / convergence / focus / ABL settings above and beyond the narrow subset that can be controlled from the menues on the monitor front panel. Problems such as "retrace lines visable" and "monitor too bright/dim" as well as many others can be fixed, keeping that monitor out of the landfill and money in your wallet.


Once the cable is in place, you will need the Sony DAS (Digital Alignment Software) to read, write and make any sense of the settings, but it seems to have been abandoned by Sony and copies of it can be found on the internet, see (cached 20080623 The actual WINDAS program is also availble at

or for a complete tutorial and for discussion. We owe a big round of thanks to "gregua" for finding, patching together and teaching us how to use this system. If he saved you the price of a new monitor, you really should chip in and:


*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.


The pin order on the TTL connector is easy to change. Just press down on the little locking pin through the slot in the plastic, and first push in, then pull out the connector by the wire. This page has a nice explanation with pictures: (cached)

SONY: The RLC-2 is the SONY 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 pins on the TTL end of the RLC-2 are already correct for the SONY ECS port. The pinout of the connector on the RLC-2 is, from top to bottom^:

Pin Color Signal Description                                                                                                                            
1. Black GND Connects to pin 1. GND on the Monitors ECS port
2. White +5V Connects to pin 2. STBY +5VDC on the Monitors ECS port
3. Yellow Tx/Dout Driven by the Monitor to send data to the PC (connects to pin 3. "RX" on the Monitors ECS port
4. Red Rx/Din Driven by the PC/RLC to send data to the Monitor (connects to pin 4. "TX" on the Monitors ECS port
5. Blue RTS unused, may need to be shorted to CTS depending on your PC and the software used.
6. Green CTS unused, may need to be shorted to RTS depending on your PC and the software used.

PANASONIC: The RLC-2 must be modified by swapping the 1st and 2nd, as well as the 3rd and 4th pins in the socket to match those on a Panasonic monitor. The pinout of the connector on Panasonic monitors is, from top to bottom:

Pin Color Signal Description                                                                                                                            
1. White +5V Connects to pin 1. STBY +5VDC on the Monitors ECS port
2. Black GND Connects to pin 2. GND on the Monitors ECS port
3. Red Rx/Din Driven by the PC/RLC to send data to the Monitor (connects to pin 3. "TX" on the Monitors ECS port
4. Yellow Tx/Dout Driven by the Monitor to send data to the PC (connects to pin 4. "RX" on the Monitors ECS port
5. Blue RTS unused, may need to be shorted to CTS depending on your PC and the software used.
6. Green CTS unused, may need to be shorted to RTS depending on your PC and the software used.

(These pinouts are known to be correct for most supported monitors, but some can be different . If you aren't sure of your monitor, use a meter to read the voltage levels on the pins of the monitors ECS port and email those readings to us with the monitor model)

HP: Brendan Hahn says "...for a D8915 chassis (HP p1120). I now have black-white-red-yellow from pin 1; works great."

RTS/CTS: On some PC's the serial port may refuse to send data until it recieves the CTS signal. You can provide this by connecting pin 5 (blue wire) of the RLC connector to pin 6 (green wire) with a little bit of bare wire bent into a jumper:


RLC-2 Datasheet


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 monitor adjustment applications; for SONY type monitors.

The RLC-2 is built into a small DB9 backshell with an 11" 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.



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.



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)



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:


file: /Techref/io/serial/rlc2.htm, 20KB, , updated: 2022/2/9 13:04, local time: 2024/7/22 02:52,

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