phil@amdcad.UUCP (Phil Ngai) (03/22/85)
With the break up of the Bell System (sniff) is there any one source of
timing for DDS? The local companies like Pacific Bell and Southwestern
Bell provide DDS service too, do they buy timing from ATT? Sometimes you
want to buy a long line from ATT, take some data out at one end, and send
the rest through a local piece of DDS to another site. For this to work,
coordinated timing would be desirable.
--
Liar liar, pants on fire. May your nose grow long as a telephone wire.
Phil Ngai (408) 749-5720
UUCP: {ucbvax,decwrl,ihnp4,allegra}!amdcad!phil
ARPA: amdcad!phil@decwrl.ARPA9212mhm@hou2a.UUCP (M.MORTENSEN) (03/23/85)
Yes, there is a currently a single source for clocking in the country. The old BSRF (formerly Bell System Reference Frequency, now called the Basic Service Reference Frequency, or some such) is still working. The Local Exchange Carriers do indeed take their DDS timing from the AT&T-C network, both for DDS as well as for digital facilities and digital switches. I have heard that some other interexchange carrier(s) may in the future be setting up their own reference sources. In that case, we will have a number of networks that are plesiochronous. Will it cause problems? It depends on how good the reference clocks are, whether the networks really worry about inadvertent timing loops, etc. Mark Mortensen AT&T-Bell Laboratories HR
dnj@faron.UUCP (David N. Juitt) (03/27/85)
In article <518@hou2a.UUCP> 9212mhm@hou2a.UUCP (M.MORTENSEN) writes: >Yes, there is a currently a single source for clocking in >the country. > . > . > . >In that case, we will have a number of >networks that are plesiochronous... > Mark Mortensen > AT&T-Bell Laboratories HR Okay, I'll bite, what does plesiochronus mean? Dave Juitt ...linus!!faron!dnj dnj@mitre-bedford