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Serial Video Text Overlay Unit



The OSDSER unit is a product only suitable for engineers, system builders and others able to write software to control it. We regret that it is not a product usable by end users such as shop keepers, cctv installers or scrap metal merchants without those skills.

The serial video text overlay unit is designed for applications where the data from a serial source needs to be displayed as a video overlay. The standard units are sold programmed with the serial command interface described below. This is provided to allow the unit to be controlled from a PC or microcontroller software program.
The unit can also be programmed with user created application specific programs. In this way users can create interfaces for any device which transmits RS232 data. It is also possible to connect digital sensors to the board within the the OSDSER unit. Our EXAMCODE example software package is available as a starting point for development. It provides example MPASM source code for interfacing the OSDSER to cash register data, GPS NMEA data, 1-Wire sensors and the MSF time signal. The OSDSER provides a simple platform for the development of microcontroller driven text over video applications. The unit uses a PIC16F628A microcontroller which allows for the use of the large amount of freely available source code on the web for sensor interfacing and other applications.


OSDSER Applications

The OSDSER unit can be directly interfaced via RS232 to GPS, Sonar or POS units. Digital sensors can also be directly connected to internal board.
DS2450 Quad 1-Wire A/D Converter

Any composite video signal source, from simple board camera to sophisticated ROVcan be connected directly to the OSDSER unit.






Keypads, buttons and switches can be connected to the internal board to drive a user interface or automatically indicate status.

Text and graphics generated by the project board can be overlaid on the video signal.



Example on screen menu

The OSDSER unit can also generate its own video signal.

We do not have a generic application which runs on the OSDSER unit to display cash register or EPOS information. If you are a EPOS system builder and control your EPOS system software you can generate commands from your system to drive the OSDSER serial command interface program described below. See the EPOS builder FAQ for details. Alternatively users may write their own application specific EPOS interface software for the OSDSER based on our EXAMCODE example. Please see our cash register FAQ for more details.

Serial Video Text Overlay Unit documentation

The OSDSER unit can be supplied with BNC connectors on request. Please email us prior to ordering.

The OSDSER unit is housed in a smart ABS plastic enclosure with phono connectors for video in / out, and a 2.1mm DC power socket. Alternatively BNC connectors can be supplied on request. It is designed to be powered from the same power supply as the camera and so the unit does not have a power switch. A 1.2m serial cable with a female DB9 connector is supplied for connecting to a PC serial port or other RS232 serial equipment.
Compatible with colour and mono composite video signals. 1Vp-p. PAL and NTSC
Automatic selection of text over external video signal or self generated video signal
256 user definable text and graphics characters
Dimensions 110 x 65 x 28mm LxWxH
Requires a regulated 9 - 12V DC power supply
High efficiency switch mode regulator ideal for battery powered applications
Power consumption 50mA
Weight 20g with serial cable
RoHS compliance

Video Overlay Character Set
The OSDSER unit is provided programmed with the character set shown below. This can be edited, modified or replaced as desired using the Maxim software and our fontset software which is available as part of our EXAMCODE example software package. Greek, Cyrillic and Hebrew character sets can be supplied as alternatives on request. As shown below when the full video frame is shown there are 16 lines of text ( PAL ). In most cases on a monitor you will see only 14 lines in PAL, 12 in NTSC.

Serial Command Interface Program

The serial command interface program allows the video overlay unit display to be controlled from a PC terminal program, microcontroller or other serial equipment. It can communicate at 2400, 4800, 9600, 19200 and 38400 baud ( 8 data 1 stop no parity ). The hyperterminal file, stv.ht, can be used to communicate with the unit. Fitness of this software for any specific purpose is specifically disclaimed.

Serial Command Interface Program Command Set

Each command consists of an upper case ASCII character which identifies the command. When a command requires a numerical parameter, shown as nn below, this parameter is entered as two ASCII numeric characters in the range 00 to 99. So 1 is entered as 01. The character string display and storage commands S & F display 28 character strings. The T command puts the system into typewriter mode. Characters are displayed on the screen as they are typed until a return is entered. Characters for display can be entered as ASCII directly from the PC keyboard.
= ASCII carriage return character, hexadecimal 0x0D. This character signals to the system that a command has been entered. The serial command interface program responds with the command prompt character >. All the serial commands take various times to execute therefore the return of the > character should be used to indicate that a command has completed.
Command Action
A Clears the entire screen. All character locations on the screen are filled with the space character.
B Toggles the character background display on and off. Current state stored in the unit
Cnn Sets the character position along the selected row ( X axis ) nn = 00..29. This value is stored in the unit and sets the position of the stored string.
D Toggles the character blink attribute on or off. The current state stored in the unit
E Displays the string stored in the unit at the character and row positions defined and stored in the unit by the C & R commands, with the attributes stored with the O command.


Stores the string entered in the eeprom memory of the unit. Up to 28 characters c0..c27 can be typed before entering a return character. The string is also displayed on the screen. The stored string is automatically displayed at start up and when the E command is entered.
Gnn Sets the character outline black level. nn = 00..03, 00 = Darkest, 03 = Lightest. Default =00
Hnn Sets the screen and character background black level. nn = 00..07, 00 = Darkest, 07 = Lightest. Default = 02
Inn Toggles the character invert attribute on or off
J Not used
K Not used
L Moves character position to the next line, character position 00
M Set the unit into external video signal mode
N Set the unit into internal video signal mode
O Store the current settings of the background, blink and invert character attributes. The stored settings are used for the display of the stored string
P Set the current values of the background, blink and invert character attributes to the stored settings
Q Reset the current values of the character attributes to background = off, blink = off and invert = off
Rnn Sets the character row position nn = 00..15 This value is stored in the unit


Displays a string of up to 28 characters. The characters typed are only displayed when return is entered
Ttext Enters typewriter mode. Text characters entered are displayed immediately on the screen until a return character is entered to exit typewriter mode
U Reset the unit to default values for character brightness, black level, screen background and X - Y display position
Vnn Not used
Wnn Change baud rate. 00 = 2400, 01 = 4800, 02 = 9600, 03 = 19200, 04 = 38400
Xnn Sets the character position along the selected row ( X axis ) nn = 00..27. This value not stored in the unit
Ynn Sets the character row position nn = 00..15. This value is not stored in the unit
Z Not used
ZB Not used
ZC Not used
ZD Not used
ZEnn Set the character brightness. nn = 00..03, 00 = Brightest, 03 = Darkest. Default = 01
ZFnn Set the vertical display offset from the top of the screen. nn = 00..31. Default = 31
ZGnn Set the horizontal display offset from the left of the screen. nn = 00..63. Default = 55
ZH Turn the background attribute of subsequent text on
ZI Turn the background attribute of subsequent text off
ZJ Turn the blink attribute of subsequent text on
ZK Turn the blink attribute of subsequent text off
ZL Turn the invert attribute of subsequent text on
ZM Turn the invert attribute of subsequent text off




© The BlackBoxCameraTM Company Limited 2016