Re: ACTS: client does not accept acts synchronized server

Uwe,

I checked NPL telephone and found it uses the * and # as per PTB. The exisitng driver code captures a timestamp at the beginning of the timecode message and at the * and # characters at the end. According to the NPL, the * or # is transmitted as the last character of the message, which is within one character (CR) of the first bit of the LF on-time event. However, the reported PTB timestamp is in error much more than that.

Question about the baud rate. NPL does not specify the baud rate; PTB specifies 1200 bps. At 1200 bps a 10-bit characgter takes 8.33 ms, so the 78-character message takes 650 ms. If the * or # was not found, the error would be near 650 ms; however, if it was found the error should depend only on the ISDN delay, which in your case is about the same here. In other words, the 51-ms error is probably due to the ISDN delay and the \\ scheme would compensate for that.

Dave

Uwe Klein wrote:
mills@xxxxxxxx wrote:

Heiko,

While this has nothing to do with the second server you cite, the 51-ms discrepancy between the PTB and GPS time is rather large. Either the telephone or modem delay is unexpectedly large or the timecode timestamp is at the wrong on-time character.

It's all ISDN and digital transfer in the Xchange?
( I get around 35/45 ms roundtrip delay via ISDN raw IP )

uwe
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