
                DCF77 radio clock information for LINUX
                =======================================


       'dcf77time' reads from a DCF77-Module ('Atom Clock') via a
       serial port the raw time transmitted at 77.5  Khz  from  a
       antenna  located  at Mainflingen near Frankfurt/Main (Ger-
       many).  The DCF77-Module is sold by  Conrad-Electronic  in
       Germany  (DCF-Modul  "WT  100  seriell"  - Order-Nr. 64 19
       60-12). It is not that accurate and doesn't  provide  date
       information, but it's very cheap (18 DM).

       'dcf77time'  is primary for use in Germany  since it relies 
       on the DCF77 signal.  But it might be  of interest  to some
       surrounding countries too.

       Conrad-Electronic says  that you can connect a Mouse to the
       same serial port,   but I don expect this to work with this
       'driver'.  Although I didn't try it.

       To connect the  DCF77-Module to the  serial port  a special
       cable is needed. Conrad sells this cable for an extra 18 DM
       together with a simple  DOS-Software.  If you want  to save
       some money and do not need the  DOS-Software you  can build 
       this cable by yourself (it's quite easy).

       Cable layout:

       serial Port  RS232-Meaning          DCF77-Module
       25pin  9pin 

         2      3    ---(TxD)-----------------  GND   (1)
         8      1    ---(DCD)-----------------  Data  (2)
         4      7    ---(RTS)-----------------  VDD   (3)
         20     4    ---(DTR)-----------------  Clock (4)


       My DCF77-Module (looking at the rear side):

       +-------------------------------------------+
       |    __    LR44                             |
       |   /  \     +        (4)(3)(2)(1)          |
       |   \  /    UP        ------------          |
       |    --                                     |
       |                                           |
       |           A  N  T  E  N  N  A             |
       +-------------------------------------------+



Copyright:	dcf77pcf is Copyright to Christian Brunner, 1996 

		This software is distributed under GPL, see the file
		COPYING for more details


Credits:        Werner Biebl    for his great UNIX teaching over the years
                                and the new 'zoneinfo'

Christian (chb@muc.de)
