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10 pps. And indeed one problem with tweaking anything to use faster pulse rates was the fact that in many instances, with mechanical switching, the dial pulsing was *directly* applied to interswitch trunk signaling systems. Early on that merely tested the ability to handle faster pulsing for all segments of a connection, but near the end of the time when SF (2600 Single Frequency) signaling was used most SF units included electronic pulse rate and make-break correction circuits. Those would not tolerate 20 pps. Anything within the 7.5 to 12 pps and 40-80 percent make break limits would be forwarded at 10pps with 60% break.
I seem to remember that Hong Kong was in fact weird, and for example used 20 pps. I'm not sure how to verify that, and haven't tried.
Here are the spec's for the North American network (from Section 62, LSSGR, Issue 2, July 1987, TR-TSY-000506.
6.2 Customer Line Signaling ... 6.2.6 Address Detection ... 188.8.131.52 Rotary Dial Pulse Detection
A customer DP receiver is required to detect DPs in the presence of all combinations of the following conditions (over all standard loop transmission facilities):
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Yes, there of course are specifications pulse speed, make-break ratios, inter-digit time, as well as minimum and maximum loop current, both for what a dial mechanism should generate...
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snip I'm trying (*), but not understanding what you mean here .... Probably not that important, though. ((*) "Very...
A. Capability for Detecting Pulses - Noncoin Lines
1. Pulsing speed 7.5 to 12 pps 2. Percent break at dial contacts 58 to 64 percent break 3. Resistance across open dial contact 50,000 ohms to infinity 4. Bridged ringers (Note 1) 0 to 5 5. External circuit resistance Range as given in LSSGR Section 6.1.5 6. Line insulation resistance 10,000 ohms to infinity
B. Capability for Detecting Pulses - Coin Lines
The same conditions apply for coin lines as listed for noncoin lines, except that a station coin magnet (Note 2) is connected from the tip lead top ground with +-- 3V earth potential.
C. Capability for Rejecting False Pulses
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The DP detection circuit should not register a false pulse under the following conditions:
1. The loop is opened for 2 ms. 2. A 274B inductor (see E-3 in this subsection) is inserted into a 1600-ohm conductor loop in two steps. The first step inserts the inductor in shunt with 1000 ohms. The second step, 25 ms later, opens the 1000-ohm shunt.
D. Recognition of Interdigital Intervals
The DP receiver should recognize off-hook intervals as short as 300 ms as an interdigital time.
When customer DPs are received at 7.5 pps with line impedances that produce minimum percent break, the make interval of the repeated pulses are distorted to a maximum length. This maximum make interval should not be interpreted as an interdigital time period.
E. Immunity to 60 Hz ac Induction
The DP detection circuit should have the capability for rejecting 60 Hz induction from ac power lines in the outside plant. All of the preceding tests should be met in the presence of induction levels stated in LSSGR 6.1.2.
The above is for dial pulsed lines. For interswitch trunks,
6.3 INTERSYSTEM DC SIGNALING ... 6.3.4 ADDRESS SIGNALING SEQUENCE ... 184.108.40.206 DIAL PULSING ... A. DP Receiving Capability
... should be able to respond to incoming DPs that have a speed between 7.5 and 12 pulses per second, and a percent break between 40 and 80 percent. ... may be designed to accept interdigital times as short at as 180 ms but is only required to accept them as short as 300 ms.
B. Outgoing DP Characteristics
The DP sending circuit in the SPCS should outpulse at rate of 9.8 to 10.2 pps with the percent break in the range of 58 to 62 percent. The interdigital time should be at least 600 ms, and it is desirable to be able to increase it to at least 700 ms if troube is experienced when sending to certain SXS machines. Furthermore, in tandem tie trunk network operation it is desirable that interdigital time be increased to as much as 1 second in some offices.
(I tried to retain the formatting, punctuation and capitalization from the original document.)
Don't ask for the specs for tone dial, as that is about 3-4 times longer! But highlights are possible if someone has questions...
The above is from TR-TSY-000506 as noted. That is a Bell Communications Research "Technical Reference" document, breastled
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Tell me about it. If I call my ISP, no matter what the problem is, the first thing the droid asks me is "What version of Windows are you...
LATA Switching Systems Generic Requirements (LSSGR)
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Right, right .... explains not being able to converse and also do something requiring thought. I can't listen to music and at the same time do anything requiring...
I don't have a full set, but do have several that are interesting.