# US 5,353,147 A · Identification of transmission characteristic > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,353,147 A - Document ID: US5353147A - Status: Granted - Kind: A - Application number: 07/800,782 - Filed: 1991-11-27 - Granted: 1994-10-04 - Earliest claimed: 1991-11-27 - Assignees: AT&T Bell Laboratories - Inventors: Gary J. Grimes - Web page: https://patentgrep.com/patent/US5353147A ## CPC - H04B 10/07: Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems - H04B: TRANSMISSION ## Abstract An apparatus to determine characteristics of an optical communication path by utilizing electrical devices in an electrical path in parallel with the optical communication path. Each electrical device is physically located with a passive or active optical device and specifies the attenuation and delay of the optical device. A receiver measures the electrical qualities of each electrical device in the electrical path which is parallel to the optical path from the optical transmitter. The electrical measurements allow the receiver to automatically adjust its optical receiver to the attenuation and delay introduced by the optical devices in the optical path. ## Claims ### Claim 1 A transmission link having a communication path with a plurality of components each effecting performance characteristics of the communication path, comprising: another communication path in conjunction with the communication path and physically distinct from the communication path; the another communication path having another plurality of components each corresponding to one of the plurality of components of the communication path; and each of the another plurality of components identifying one or more characteristics of the corresponding component of the plurality of components. ### Claim 2 (depends on 1) The transmission link of claim 1 wherein the plurality of components are electrical components and the other plurality of components are also electrical components. ### Claim 3 (depends on 2) The transmission link of claim 2 wherein each of the other plurality of components is a resistor. ### Claim 4 (depends on 2) The transmission link of claim 2 wherein each of the other plurality of components is a resistor and inductor which are interconnected. ### Claim 5 (depends on 2) The transmission link of claim 2 wherein each of the other plurality of components is an active electrical circuit for inserting information into the other communication path. ### Claim 6 (depends on 1) The transmission link of claim 1 wherein the plurality of components are optical components and the another plurality of components are electrical components. ### Claim 7 (depends on 6) The transmission link of claim 6 wherein each of the another plurality of components is a resistor. ### Claim 8 (depends on 6) The transmission link of claim 6 wherein each of the another plurality of components is a resistor and inductor which are interconnected. ### Claim 9 (depends on 6) The transmission link of claim 6 wherein each of the another plurality of components is an active electrical circuit for inserting information about the corresponding optical component of each into the another communication path. ### Claim 10 (depends on 6) The transmission link of claim 6 wherein the communication path is an optical link interconnecting an optical receiver and an optical transmitter whose output may be dangerous to human eyes; and means connected to the other communication path for transmitting signals on the another communication path and located with the optical transmitter; means connected to the other communication path for receiving the transmitted signals and for retransmitting the received signals to the transmitting means via the another communication path; and the transmitting means responsive to receipt of the retransmitted signals for enabling the operation of the optical transmitter and responsive to the absence of the retransmitted signals for inhibiting the operation of the optical transmitter. ### Claim 11 (depends on 6) The transmission link of claim 6 wherein the communication path is an optical link interconnecting an optical receiver and an optical transmitter and means located with the optical transmitter and connected to the other communication path for transmitting a packet on the another communication path; each of the another plurality of components is an active electrical circuit for inserting information identifying the optical component type of the optical component corresponding to each of the another plurality of components into the another communication path upon receipt of the packet; means located with the optical receiver and connected to the another communication path for receiving the packet and for retransmitting the received packet to the transmitting means via the another communication path; and the transmitting means responsive to receipt of the retransmitted packet for communicating the retransmitted packet to a system computer whereby the system computer determines the optical components in the optical link. ### Claim 12 An apparatus for measuring performance characteristics of a communication path in a transmission link, and the communication path having a plurality of components each effecting the performance characteristics of the communication path, comprising: first means connected to the communication path for transmitting signals on the communication path; means connected to the communication path for receiving signals from the communication path; another plurality of components in another communication path in conjunction with the communication path, and each of the another plurality of components corresponding to one of the plurality of components of the communication path; second means connected to the another communication path for transmitting signals through the another communication path; each of the another plurality of components responsive to the signals for identifying one or more performance characteristics of the corresponding component of the plurality of components by modifying the signals; means connected to the another communication path for determining the performance characteristics of the communication path in response to the signals received from the another communication path; and the receiving means connected to the determining means is responsive to the performance characteristics for adjusting to match the performance characteristics. ### Claim 13 (depends on 12) The apparatus of claim 12 where the receiving means is responsive to being unable to adjust for the performance characteristics for transmitting a signal to a system processor. ### Claim 14 (depends on 12) The apparatus of claim 12 where the other communication path provides a return path for the received signals from the determining means back to the second transmitting means; and the second transmitting means is responsive to the absence of the returned signals for inhibiting the transmission by the first transmitting means. ### Claim 15 (depends on 14) The apparatus of claim 14 wherein the second transmitting means is further responsive the absence of the returned signals for signaling another system processor. ### Claim 16 (depends on 12) The apparatus of claim 12 wherein the plurality of components are electrical components and the other plurality of components are electrical components. ### Claim 17 (depends on 16) The apparatus of claim 16 wherein each of the other plurality of components is a resistor; the second transmitting means transmits an electrical current; and the determining means measures the resistance of the resistors in the other communication path by a voltage drop to determine one performance characteristic of the communication path. ### Claim 18 (depends on 17) The apparatus of claim 17 where the other communication path provides a return path for current received from the second transmitting means by the determining means back to the second transmitting means; and the second transmitting means responsive to the absence of the returned current for inhibiting the transmission by the first transmitting means. ### Claim 19 (depends on 18) The apparatus of claim 18 where the determining means responsive to the absence of current for sending a signal to a system controller. ### Claim 20 (depends on 18) The apparatus of claim 18 where the second transmitting means further responsive to the absence of the returned current for sending a signal to another system controller. ### Claim 21 (depends on 16) The apparatus of claim 16 wherein each of the other plurality of components comprises a resistor and inductor which are interconnected; the second transmitting means alternates between transmission of a DC electrical current and AC electrical current; and the determining means measures the resistance of the resistors in response to the DC electrical current in the other communication path to determine one performance characteristic of the communication path and measures the inductance of the inductors in response to the AC electrical current in the other communication path to determine another performance characteristic of the communication path. ### Claim 22 (depends on 16) The apparatus of claim 16 wherein each of the other plurality of components is an active electrical circuit; the second transmitting means transmits a data packet; each active electrical circuit is responsive to receipt of the data packet to insert data into the data packet defining performance characteristics of the corresponding one of the plurality of components; and the determining means responsive to the data packet for recovering performance information for each of the plurality of components. ### Claim 23 (depends on 22) The apparatus of claim 22 where the other communication path provides a path for returning the packet received from the second transmitting means by the determining means back to the second transmitting means; and the second transmitting means responsive to the absence of the returned packet for inhibiting the transmission by the first transmitting means. ### Claim 24 (depends on 23) The apparatus of claim 23 where the second transmitting means responsive to information in the returned packet for determining if the the first transmitting means should be inhibited. ### Claim 25 (depends on 24) The apparatus of claim 24 where the second transmitting means further responsive to information in the returned packet indicating that the first transmitting means should be inhibited for sending a message to to a system controller. ### Claim 26 (depends on 24) The apparatus of claim 24 where the second transmitting means further responsive to the returned packet to transmit the returned packet to a system controller. ### Claim 27 (depends on 16) The apparatus of claim 16 wherein each of the other plurality of components is an active electrical circuit; the second transmitting means transmits a data packet; each electrical circuit is responsive to receipt of the data packet to insert data into the data packet defining performance characteristics of the corresponding one of the plurality of components; and the determining means responsive to the data packet for recovering performance information for each of the plurality of components. ### Claim 28 (depends on 27) The apparatus of claim 27 wherein each of the other plurality of components is an active electrical circuit; the second transmitting means transmits a data packet; each active electrical circuit is responsive to receipt of the data packet to insert data into the data packet defining performance characteristics of the corresponding one of the plurality of components; and the determining means responsive to the data packet for recovering performance information for each of the plurality of components. ### Claim 29 (depends on 28) The apparatus of claim 28 where the other communication path provides a path for returning the packet received from the second transmitting means by the determining means back to the second transmitting means; and the second transmitting means responsive to the absence of the returned packet for inhibiting the transmission by the first transmitting means. ### Claim 30 (depends on 29) The apparatus of claim 29 where the second transmitting means responsive to information in the returned packet for determining if the the first transmitting means should be inhibited. ### Claim 31 (depends on 30) The apparatus of claim 30 where the second transmitting means further responsive to information in the returned packet indicating that the first transmitting means should be inhibited for sending a message to to a system controller. ### Claim 32 (depends on 31) The apparatus of claim 31 where the second transmitting means further responsive to the returned packet to transmit the returned packet to a system controller. ### Claim 33 (depends on 12) The apparatus of claim 12 wherein the plurality of components are optical components and the another plurality of components are electrical components. ### Claim 34 (depends on 33) The apparatus of claim 33 wherein each of the another plurality of components is a resistor; the second transmitting means transmits an electrical current; and the determining means measures the resistance of the resistors in the other communication path by a voltage drop to determine one performance characteristic of the communication path. ### Claim 35 (depends on 34) The apparatus of claim 34 where the another communication path provides a return path for current received from the second transmitting means by the determining means back to the second transmitting means; and the second transmitting means responsive to the absence of the returned current for inhibiting the transmission by the first transmitting means. ### Claim 36 (depends on 35) The apparatus of claim 35 where the determining means responsible to the absence of current for sending a signal to a system controller. ### Claim 37 (depends on 35) The apparatus of claim 35 where the second transmitting means is further responsive to the absence of the returned current for sending a signal to another system controller. ### Claim 38 (depends on 33) The apparatus of claim 33 wherein each of the another plurality of components comprises a resistor and inductor which are interconnected; the second transmitting means alternates between transmission of a DC electrical current and AC electrical current; and the determining means measures the resistance of the resistors in response to the DC electrical current in the another communication path to determine one performance characteristic of the communication path and measures the inductance of the inductors in response to the AC electrical current in the another communication path to determine another performance characteristic of the communication path.