[RTTY] Icom CI-V with Transistors

[Jim W7RY]

An excerpt from this site: http://www.wa0sxv.us/ci-v.html


Also of interest is the fact that, although they work, solutions 
involving the Icom OPC-478 cable and variants which use two or three 
transistors, use the serial interface power,  and don't necessarily 
generate a negative voltage may actually violate the RS232 signal 
standards.  As such, they may be vulnerable to numerous maladies 
including lack of noise tolerance and possible rate and content related 
errors.  The MAX2xx line of chips actually include voltage doublers and 
generators of negative voltage.  Only one of the discrete component 
designs I've seen actually does this.  Compliance with these standards 
can be measured with a voltmeter or examined visually using anRS232 
signal display <http://www.wa0sxv.us/rs232board.html>.  Another drawback 
of the port-powered interfaces is that they simply may not work on many 
laptops due to the lack of necessary control signals on the serial port.

73
Jim W7RY


On 1/15/2014 9:39 PM, Jim W7RY wrote:
> Has anyone used the "transistor type" of serial to TTL (CI-V) 
> converter?  Had any issues?  I've built one with the MAX232 chip and 
> it works fine.
>
> If anyone has had issues with a transistor type, please let me know.
> 73
> Jim W7RY
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