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- From: az325@FreeNet.Carleton.CA (Scott Fender)
- Subject: Re: ESS & DMS Question
-
- In a previous posting, Lee Hardiman (hardiman@pic.net) writes:
- > In article <3nn9q5$55u@newsbf02.news.aol.com>, missevian@aol.com says...
- > I'm not a phreaker or anything but I keep hearing these two acronyms
- > (ESS & DMS) and I'd appreciate a little info on what the difference is
- > between the two and how it affects the phone your using. Thanx.
- >
- > ESS stands for Electronic Switching System and is a term used to refer to
- > switches manufactured by AT&T. DMS is a trademark of Northern Telecom.
- > Both refer to switches that use a computer to control the switch matrix.
- > A DMS, #5ESS, nad #4ESS are digital switches. A #1ESS uses an analog
- > switch matrix.
- >
-
- Also to complete, it "DMS" simply stands for "Digital Multiplex Switch".
- Common DMS versions are:
- DMS-10 -serves areas a bit outside the main city centres. It links
- small communities to a larger DMS-100 located in a larger city.
- DMS-100 -This is the local exchange. Used all over Canada except in rare
- cases where No. 5 X-Bar is in use, and in even more rare cases
- where SxS is still running. It is programmed in BNR proprietary
- Pascal, in PROTEL, and in Assembler (rarely these days).
- It is upgraded by software loads that take place every six months,
- with *major* software changes taking place every 18 months.
- The loads take place at 3 AM local time. These BCS loads
- (Batch Change Supplements) can be quite take longer than expected
- sometimes, and weird things can happen. Because of this the
- switch is always "mirrored" prior to any new load and can revert
- back to its former state if the trouble persists. To simplify
- the load process, the loads are now done via PCL's, which are
- smaller and take advantage of more modular software currently
- written. Each PCL is specific for each individual switch
- operating in North America.
- DMS-200 -This is a local operating company toll switch.
- DMS-250 -This switch local/toll used by the inter exchange carriers MCI,
- Sprint etc.
- DMS-300 -This is a ISC switch and can do all the conversion between the
- International circuit (CCITT System No. 5) and various North
- American systems like R1 (Regional System No. 1), SS6, and
- SS7.
-
- Both AT&T's switches and NT's (BNR designed) DMS switches are quite advanced.
- They can "get" you if they want to.
-
- Take it easy guys,
- Scott. (az325@freenet.carleton.ca)
-
-
- P.S. Hope to see you all at Cafe Wim (Ottawa) this Friday.
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