The Interface
       

Pinouts and cables for telecomms

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Interface pinout and electrical information.

 
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These are short descriptions of the interfaces available from the menu on the left at the bottom of this page . The information is as accurate as I can make it , if you spot mistakes let me know.
 
Digital Interface Voltage Comparisons
 
LOGIC STATE CCITT RECOMMENDATION
Control Data V.28 V.35 V.11 X.21 RS 449
Minimum Input Voltages OFF 1 -3v < -70 mV <-0.3v <-0.3v <-0.3v
ON 0 +3v >+70mV >+0.3v >+0.3v >+0.3v
Typical Output  Voltages OFF 1 -5 .. -12v -0.55v -3v -3v -3v
ON 0 +5 .. +12v +0.55v +3v +3v +3v
Recommended connector type 25 way D-Type 34 way square 15 way D-Type 37 way D-Type
 
 
These are short descriptions of the interfaces available from the menu on the left. The information is as taken from many different sources too numerous to mention. If what you require is not here try technick ,this site is excellent for hardware and interface information.
 
   
X.21 / V.11
X.21 defines the physical characteristics for a general interface between DTE and DCE using synchronous transmission on public data networks . This interface is extensively used for 64Kb circuits and 56Kb/s (USA and Japan).
 

RS 449
RS449 redefines RS232 and was intended to replace it . This recommendation includes several CCITT V.24 circuits which were not included in RS-232 and they are 140,141,142,126,116 and 117. It also specifies that for data rates higher than 20Kb/s ten V.24 circuits should have balanced circuits and use V.11 / RS422 voltage levels making them compatable with CCITT X.21 .
 

V.35
V.35 describes the modulation methods for 48Kb/s synchronous full duplex data communication circuits. It also redefines the V.24 circuits 103,104,114 and 115 to make them balanced circuits.
 

RJ45
RJ45 Connector as used for UTP and ISDN S-Bus / PRA 2mb presentation connections.
 

IEEE 488
This interface is for Programmable Instrumentation using a Data Bus between instruments to transfer data to and from the various instruments connected.
 

RS 232
Most computers,terminals,printers and modems have a familiar connector with either 9 pin D-Type or 25 pin D-Type , if so this connector probably conforms to the CCITT V.24 / RS232 standard.
 

Laplink
25 Pin male to 25 Pin male connector used between two PC's running LAPLINK software.
 

Centronics
The Centronics Parallel interface has become accepted as the standard connector used between a PC and a Printer.The interface carries an 8 bit byte in parallel which is clocked in to the printer using the STROBE pulse signal supplied by the Computer (PC).
 

PC Com Port
Programmers only , indepth information about the PC serial port. This file is 126Kb and has not yet been tidied up for web publication.
 

U.S.B.
Just about any computer that you buy for your home or office today comes with one or more Universal Serial Bus connectors on the back. These USB connectors let you attach everything from mice to printers to your computer quickly and easily.
 

Firewire
FireWire uses 64-bit fixed addressing, based on the IEEE 1212 standard.Developed by Apple Computers and often found on Video Cameras.
 

 
 

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  If you find this useful and have information to add email Martin Ryan. All contributions , queries and constructive criticisms are welcome.  
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