Browse Prior Art Database

DYNAMIC RING VALIDATION USING CYCLICAL PATTERN RECOGNITION

IP.com Disclosure Number: IPCOM000026171D
Original Publication Date: 1990-Aug-31
Included in the Prior Art Database: 2004-Apr-05
Document File: 4 page(s) / 227K

Publishing Venue

Xerox Disclosure Journal

Abstract

The use of embedded modems for Remote Interactive Communications (RIC), enables electroreprographic machines to interactively communicate with an external host system. A dificulty in implementation of the RIC system is the lack of a standard set of ring characteristics across international PBX systems. For example, the Bell standard ring, illustrated in Figure la, utilizes a 2 second ring pulse, denoted by the active-low Ring Detect pulse, and a 4 second interim or dead period between active ring pulses. This standard ring cycle poses little problem for a modem to detect and answer. However, certain 'European' style ring systems, utilize an alternative ring sequence, comprising a series of two, or optionally three, ring pulses for each ring cycle. This alternative ring sequence is illustrated in Figure lb. In the two pulse case, the first ring pulse is present for a time period XI, after which no pulse is present for a period Y 1. Following the dead period, a second ring pulse is received for time X2, again followed by a dead period Y2. Optionally, this sequence may be repeated for a third time as illustrated by X3. The ring cycle is then completed by a longer interim period where no ring signal is sent.

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Page 1 of 4

XEROX DISCLOSURE JOURNAL

DYNAMIC RING VALIDATION Proposed Classification USING- CYCLICAL PATTERN U.S. C1.379/096
RE COGNITION Int. C1. H04M William T. Ho

: 2sec : 4 sec

-1 7

Ring Cycle 1 Ring Cycle 2

Ring Detect

FIG. la

.. ..

- .. ..

I Ring Detect I I I I I

I I

I I I I

L---A L---,

Ring Cycle 1 Ring Cycle 2

FIG. lb

XEROX DISCLOSURE JOURNAL - Vol. 15, No. 4 July/August 1990 281

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DYNAMIC RING VALIDATION USING CYCLICAL PATTERN RE C OGNITION(Cont'd)

STANDBY I

---_--------

____--__--

Ring Detect

___________--_-----_

Invalid Time Clear All Memory, Reinitialize

Cycles = MAX. Cycles

____---____---

Increment Ring Count

-- -_-- --___---

I VAL1 DATl ON li

Ring Detect Start Cvcle Timer

Cycle Timer Timeout
Initialize Cycles
= 1

__-_-_ -__---

I RINGDETECTED

rD ET E RM I N E Rl"l E (XN')1

Valid Ring Period Store Ring Time (XN')

---____----_--

XN = X"

_--___---__---

Valid Dead Period Increment Ring Count

 Cycles < MAX. Cycles increment Cycle Count

_----__- --_-

Start Dead Timer

I DETERMINE DEAD TIME (YN) 1

I I

I I

CHECK MAX. CYCLES

---___---__---

I

---- -_-___---_

Answer Phone

4 I ANSWER I FIG. 2

282 XEROX DISCLOSURE JOURNAL - Vol. 15, No. 4 July/August 1990

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Page 3 of 4

DYNAMIC RING VALIDATION USING CYCLICAL PATTERN RE C 0 GNITION(Cont'd)

The use of embedded modems for Remote Interactive Communications (RIC), enables electroreprographic machines to interactively communicate with an external host system. A dificulty in implementation of the RIC system is the lack of a standard set of ring characteristics across international PBX systems. For example, the Bell standard ring, illustrated in Figure la, utilizes a 2 second ring pulse, denoted by the active-low Ring Detect pulse, and a 4 second interim or dead period between active ring pulses. This standard ring cycle poses little problem for a modem to detect and answer. However, certain 'European' style ring systems, utilize an alternative ring sequence, comprising a series of two, or optionally three, ring pulses for each ring cycle. This alternative ring sequence is illustrated in Figure lb. In the two pulse case, the first ring pulse is present for a time period XI, after which no pulse is present for a period Y 1. Following the dead period, a second ring pulse is received for time X2, again followed by a dead period Y2. Optionally, this sequence may be repeated for a third time as illustrated by X3. The ring cycle is then completed by a longer interim period where no ring signal is sent.

The difficulty in detecting the alternative ring pulses arises when a modem attempts to detect and verify the presence of a ring pulse. Due to the relatively short duration of the pulses, as illustrated by Xi and X2, certain ring pulses may appear similar to line noise and therefore be ignored by the communications interface. For the reasons described, it was necessary to implement a communica...