Yes, the T-DSL's splitter (Breitband-Anschluss-Einheit - BBAE) prevents eyeSDN correctly from being irritated by irrelevant signals.
In Restricted Mode, eyeSDN should not light up since the little energy available is required for the emergency telephone. If - despite apparently correct power supply - eyeSDN does not want to light up, it perhaps runs in Restricted Mode. This can be checked by a voltage measurement:
The voltage must be always there - even if eyeSDN does not light up. It occurred already that the NT1 did not get supply from the mains, although the power supply plug was inserted. (At several NT1s, the green lamp does not confirm the successful supply from the mains, but the data link to the switching center instead).
No problem. The NT1 is still listening on the S/T bus whether somebody wants to re-use the phone. After half a minute, it gives up. After connections with mobile phones, it can last more than five times that long.
eyeSDN lights up whenever the S/T bus is not silent: Not only both expected und unexpected data communication make it light up, also spurious signals can be the cause. A reason more to sound the things out ...
It has been known to happen that the software was hung in a TE1. Then the display did not go out by itself either. The U connection had to be interrupted briefly, as is described in the footnote***).
The S/T bus must always be correctly terminated at its two outermost ends (only there and nowhere else) in order to comply with the high-frequency network termination rules**). (For the following experiments, the termination resistors are assumed not to reside in your TE1s, rather in the S/T bus wall outlets - in the NT1 if appropriate.)
Try to find out, which one of your TE1s makes eyeSDN to light up continuously - by unplugging one by one off the S/T bus. When only the empty (however still correctly terminated) S/T bus is plugged to the NT1 at the latest, the lamp of the likewise plugged eyeSDN must go out after a waiting period of half a minute, as long as no data traffic is coming from the exchange line. If your S/T bus is OK, you possibly should call on your telephone provider, since you might have rented the service feature "continuous monitoring at the BRI".
Actually, there are still PBXs (e.g. yours) and TE1s***), which do not leave the S/T bus in peace as soon as the wanted traffic terminates - even after having waited half a minute.
The particular reason for this cannot always be assessed from here immediately - perhaps the CPI's manual can know it, otherwise its installer, but definitely the manufacturer. If there is no comprehensible reason for this irritating traffic, it has to be abolished, so eyeSDN can provide its monitoring function. (Therefore some manufacturers offer firmware updates by download.) Otherwise it is as if you would have sealed the spy-hole at your entry door, so you do not have to see who is standing outside.
It makes little sense to install eyeSDN on the internal S/T bus, since you probably want to uncover attacks on your purse. Therefore eyeSDN has to monitor the external S/T bus - it is that S/T bus, which is next to the switching center (where the cost accounting takes place), thus the S/T bus at the NT1.
In the footnote***), only those devices have been specified, that have become known as troublemakers so far. If your device is not named there, then it is either compliant or not tested yet.
No. To manage this, the data protocol should be evaluated - by means of an ISDN protocol analyser (see also FUNKSCHAU 7/2000 page 65 and FUNKSCHAU 14/2000 page 67). Yet, eyeSDN is an OSI layer-1 inspector: It works free of protocol on OSI layer 1 only, thus cannot be tricked by any protocol (protocols work starting at layer 2 only and above).
Also, German TELEKOM's installation tester 40146248EA A3 ISDN Inhouse tester (Kudibel) is not a back-up for eyeSDN - even if Christian Spanik inadvertently suggests something else in his contribution about eyeSDN to the bargain counter in the first CHIPtv issue.
Yes. eyeSDN is available as module without housings. The interface to the LED supplies 26 mA and is the perfect input to an opto coupler for the galvanic isolation of any device from the S/T bus.
***) for example, from German TELEKOM, the telephones Europe 12, Europe 20i (HAGENUK EuroPhone L) and Europe 40i (HAGENUK EuroPhone XL) or the telephone TELES TELES.FON or a PC board from TELES or the TA of the DeTeWe twinny nova or the TA HAGENUK Databox Speed Dragon or the TA 2 a/b Komfort as subsidized by German TELEKOM, from DeTeWe or from German TELEKOM the TA Teledat (150) USB 2 a/b (requires firmware update) from AVM or the system Eumex 404PC from German TELEKOM or a CISCO router of the 2600 series.
One can outwit such devices: Disturbing traffic on the S/T bus stops immediately, when one interrupts and restores the NT1's connection to the switching center of the telephone provider. That is the U connection through the 6-pole (coded RJ11-)plug with two contacts (black, leftmost at the NT1 in the following picture).
One can insert a breaking pushbutton into the U line to the NT1. A single-pole breaking switch in one of the two used wires is sufficient. If an extension becomes necessary, it may be any length. Caution is required, since 100 V reside on the U line - it tickles quite noticeably when touching. Thus: Do not work under tension.
Some English technical terms in German (by
http://www.t-versand.de/isroot/tversand/static/lexikon/lexikon.html et al.):
Rough automatic translation
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