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| author | roberto <roberto@FreeBSD.org> | 1999-12-09 13:01:21 +0000 |
|---|---|---|
| committer | roberto <roberto@FreeBSD.org> | 1999-12-09 13:01:21 +0000 |
| commit | ef64b99e8412f2273dd2e8b3291c2f78ffc4667f (patch) | |
| tree | fc0cfa1aab0ff6b228f511b410733ef4f35d1ead /contrib/ntp/html/driver19.htm | |
| download | FreeBSD-src-ef64b99e8412f2273dd2e8b3291c2f78ffc4667f.zip FreeBSD-src-ef64b99e8412f2273dd2e8b3291c2f78ffc4667f.tar.gz | |
Virgin import of ntpd 4.0.98f
Diffstat (limited to 'contrib/ntp/html/driver19.htm')
| -rw-r--r-- | contrib/ntp/html/driver19.htm | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/contrib/ntp/html/driver19.htm b/contrib/ntp/html/driver19.htm new file mode 100644 index 0000000..a5cd5e0 --- /dev/null +++ b/contrib/ntp/html/driver19.htm @@ -0,0 +1,124 @@ +<HTML> +<HEAD> + <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> + <META NAME="GENERATOR" CONTENT="Mozilla/4.01 [en] (Win95; I) [Netscape]"> + <TITLE>Heath WWV/WWVH Receiver +</TITLE> +</HEAD> +<BODY> + +<H3> +Heath WWV/WWVH Receiver</H3> + +<HR> +<H4> +Synopsis</H4> +Address: 127.127.19.<I>u</I> +<BR>Reference ID: <TT>WWV</TT> +<BR>Driver ID: <TT>WWV_HEATH</TT> +<BR>Serial Port: <TT>/dev/heath<I>u</I></TT>; 1200 baud, 8-bits, no parity +<BR>Features: <TT>tty_clk</TT> +<BR>Requires: <TT>/usr/include/sys/termios.h</TT> header file with modem +control +<H4> +Description</H4> +This driver supports the Heath GC-1000 Most Accurate Clock, with RS232C +Output Accessory. This is a WWV/WWVH receiver somewhat less robust than +other supported receivers. Its claimed accuracy is 100 ms when actually +synchronized to the broadcast signal, but this doesn't happen even most +of the time, due to propagation conditions, ambient noise sources, etc. +When not synchronized, the accuracy is at the whim of the internal clock +oscillator, which can wander into the sunset without warning. Since the +indicated precision is 100 ms, expect a host synchronized only to this +thing to wander to and fro, occasionally being rudely stepped when the +offset exceeds the default CLOCK_MAX of 128 ms. + +<P>The internal DIPswitches should be set to operate at 1200 baud in MANUAL +mode and the current year. The external DIPswitches should be set to GMT +and 24-hour format. It is very important that the year be set correctly +in the DIPswitches; otherwise, the day of year will be incorrect after +28 April of a normal or leap year. + +<P>In MANUAL mode the clock responds to a rising edge of the request to +send (RTS) modem control line by sending the timecode. Therefore, it is +necessary that the operating system implement the <TT>TIOCMBIC</TT> and +<TT>TIOCMBIS</TT> ioctl system calls and <TT>TIOCM_RTS</TT> control bit. +Present restrictions require the use of a POSIX-compatible programming +interface, although other interfaces may work as well. + +<P>The clock message consists of 23 ASCII printing characters in the following +format: +<PRE>hh:mm:ss.f dd/mm/yr<cr> + +hh:mm:ss.f = hours, minutes, seconds +f = deciseconds ('?' when out of spec) +dd/mm/yr = day, month, year</PRE> +The alarm condition is indicated by '?', rather than a digit, at A. Note +that 0?:??:??.? is displayed before synchronization is first established +and hh:mm:ss.? once synchronization is established and then lost again +for about a day. + +<P>A fudge time1 value of .07 s appears to center the clock offset residuals. +<H4> +Fudge Factors</H4> + +<DL> +<DT> +<TT>time1 <I>time</I></TT></DT> + +<DD> +Specifies the time offset calibration factor, in seconds and fraction, +with default 0.0.</DD> + +<DT> +<TT>time2 <I>time</I></TT></DT> + +<DD> +Not used by this driver.</DD> + +<DT> +<TT>stratum <I>number</I></TT></DT> + +<DD> +Specifies the driver stratum, in decimal from 0 to 15, with default 0.</DD> + +<DT> +<TT>refid <I>string</I></TT></DT> + +<DD> +Specifies the driver reference identifier, an ASCII string from one to +four characters, with default <TT>WWV</TT>.</DD> + +<DT> +<TT>flag1 0 | 1</TT></DT> + +<DD> +Not used by this driver.</DD> + +<DT> +<TT>flag2 0 | 1</TT></DT> + +<DD> +Not used by this driver.</DD> + +<DT> +<TT>flag3 0 | 1</TT></DT> + +<DD> +Not used by this driver.</DD> + +<DT> +<TT>flag4 0 | 1</TT></DT> + +<DD> +Not used by this driver</DD> +</DL> +Additional Information + +<P><A HREF="refclock.htm">Reference Clock Drivers</A> +<HR> +<ADDRESS> +David L. Mills (mills@udel.edu)</ADDRESS> + +</BODY> +</HTML> |
