[Bug 357] Fixed and additional improvements from Dave Mills

bk: 41b3e120Bpim5hPq_fwZ5orSLDzWjA

diff --git a/html/drivers/driver18.html b/html/drivers/driver18.html
index 6b0e86a4196b824b4745ee23caf43ceb27878121..b91211434ec9f1628bce0fad8900cb69fd648f36 100644 (file)
--- a/html/drivers/driver18.html
+++ b/html/drivers/driver18.html
@@ -20,10 +20,10 @@
             Requires: <tt>/usr/include/sys/termios.h</tt> header file with modem control</p>
         <h4>Description</h4>
                <p>This driver supports the US (NIST and USNO) and European (PTB (Germany), NPL (UK), etc.) modem time services, as well as Spectracom GPS&nbsp;and WWVB receivers connected via a modem. The driver periodically dials a number from a telephone list, receives the timecode data and calculates the local clock correction. It is designed primarily for backup when neither a radio clock nor connectivity to Internet time servers are available.</p>
-               <p>For best results the indicated time must be corrected for the modem and telephone circuit propagation delay, which can be 200 ms or more. For the NIST service, corrections are determined automatically by measuring the roundtrip delay of echoed characters. With this service the absolute accuracy is typically a millisecond or two. Corrections for the other services must be determined by other means. With these services variations from call to call and between messages during a call are typically a rew milliseconds, occasionally higher.</p>
+               <p>For best results the indicated time must be corrected for the modem and telephone circuit propagation delay, which can be 200 ms or more. For the NIST service, corrections are determined automatically by measuring the roundtrip delay of echoed characters. With this service the absolute accuracy is typically a millisecond or two. Corrections for the other services must be determined by other means. With these services variations from call to call and between messages during a call are typically a few milliseconds, occasionally higher.</p>
                <p>This driver requires a 9600-bps modem with a Hayes-compatible command set and control over the modem data terminal ready (DTR) control line. The actual line speed ranges from 1200 bps with USNO&nbsp;to 14,400 bps with NIST. The modem setup string is hard-coded in the driver and may require changes for nonstandard modems or special circumstances.</p>
                <p>There are three modes of operation selected by the <tt>mode</tt> keyword in the <tt>server</tt> configuration command. In manual mode (2) the calling program is initiated by setting fudge <tt>flag1</tt>. This can be done using <tt>ntpdc</tt>, either manually or via a cron job. In auto mode (0) <tt>flag1</tt> is set automatically at each poll event. In backup mode (1) <tt>flag1</tt> is set automatically at each poll event, but only if the prefer peer is unreachable. </p>
-               <p>When <tt>flag1</tt> is set, the calling program dials each number listed in the <tt>phones</tt> command of the configuration file in turn. The number is specified by the Hayes ATDT prefix followed by the number itself, including the prefix and long-distance digits and delay code, if necessary. The <tt>flag1</tt> is reset and the calling program terminated if (a)  valid clock update has been determined, (b) no more numbers remain in the list, (c) a device fault or timeout occurs or (d) fudge <tt>flag1</tt> is reset manually using <tt>ntpdc</tt>.</p>
+               <p>When <tt>flag1</tt> is set, the calling program dials the first number in the list specified by the <tt>phone</tt> command. If the call fails for any reason, the program dials the second number and so on. The number is specified by the Hayes ATDT prefix followed by the number itself, including the prefix and long-distance digits and delay code, if necessary. The <tt>flag1</tt> is reset and the calling program terminated if (a)  valid clock update has been determined, (b) no more numbers remain in the list, (c) a device fault or timeout occurs or (d) fudge <tt>flag1</tt> is reset manually using <tt>ntpdc</tt>.</p>
                <p>The driver is  transparent to the message format of each modem time service and Spectracom radio. It selects the parsing algorithm depending on the message length. There is some hazard should the message be corrupted. However, the data format is checked carefully and only if all checks succeed is the message accepted. Corrupted lines are discarded without complaint. Once the service is known, the reference identifier for the driver is set to NIST, USNO, PTB or WWVB as appropriate.</p>
                <p>Ordinarily, the serial port is connected to a modem; however, if fudge <tt>flag3</tt> is set, it can be connected directly to a device or another computer for testing or calibration. In principle, fudge <tt>flag2</tt> enables port locking, allowing the modem to be shared when not in use by this driver. At least on Solaris with the current NTP I/O routines, this results in lots of ugly error messages.</p>
                <p>The <tt>minpoll</tt> and <tt>maxpoll</tt> keywords of the server configuration command can be used to limit the intervals between calls. Ordinarily, the poll interval follows the system poll interval, but not less than the minpoll specification. should ramp up over time to over a day.</p>