# US 10,122,850 B2 · Support of non-secure warning tones on packet-switched networks, particularly across multiple security domains > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,122,850 B2 - Document ID: US10122850B2 - Status: Granted - Kind: B2 - Application number: 14/267,442 - Filed: 2014-05-01 - Published: 2014-11-06 - Granted: 2018-11-06 - Earliest claimed: 2013-05-02 - Assignees: Paradigm Services Limited - Applicants: Paradigm Services Limited - Inventors: Christopher Benjamin Wakely; Kevin John Warbrick - Web page: https://patentgrep.com/patent/US10122850B2 ## CPC - H04M 3/436: Arrangements for screening incoming calls {, i.e. evaluating the characteristics of a call before deciding whether to answer it (based on the calling party profile H04M3/42059; based on location H04M3/42348; based on presence H04M3/42365; diversion H04M3/54)} - H04L 63/14: {for detecting or protecting against malicious traffic} - H04L 65/103: {in the network} - H04L 65/104: {in the network} - H04L 65/1069: Session establishment or de-establishment - H04M 3/205: {Eavesdropping prevention - indication of insecurity of line or network} - H04M 7/0078: {Security; Fraud detection; Fraud prevention} - H04L 63/105: {Multiple levels of security} - H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A method for supporting non-secure warning tones on packet-switched networks involves receiving a call attempt from a source phone to a destination phone, checking if a connection of the security domains of the source phone and the destination phone via a MLS voice gateway is allowed, and checking if a generation of a non-secure warning tone locally by the source phone is required. A call is established from the source phone to the destination phone upon acknowledgement of the local generation of the non-secure warning tone by the source phone. ## Claims ### Claim 1 A method for supporting non-secure warning tones on packet-switched networks comprising the steps of: receiving, by a Multi-Level Secure (MLS) voice gateway, a call attempt from a source phone to a destination phone; checking, by the MLS voice gateway, if a connection of security domains of the source phone and the destination phone via the MLS voice gateway is allowed; checking, by the MLS voice gateway, if a generation of a non-secure warning tone locally by the source phone is required; receiving, by the MLS voice gateway, an acknowledgement of a local generation of the non-secure warning tone by the source phone; and establishing, by the MLS voice gateway, a cross-security domain call from the source phone to the destination phone. ### Claim 2 (depends on 1) The method of claim 1, wherein the step of checking if the connection of the security domains of the source phone and the destination phone via a MLS voice gateway is allowed comprises the steps of: checking if the security domains of the source phone and the destination phone are compatible; and allowing the call attempt based on the step of checking if the security domains of the source phone and the destination phone are compatible. ### Claim 3 (depends on 1) The method of claim 1, wherein the step of checking if a generation of a non-secure warning tone locally by the source phone is required comprises the steps of: checking if a warning is required for connecting the security domains of the source phone and the destination phone via a MLS voice gateway; and signaling to the source phone that the local generation of the non-secure warning tone is required, and waiting for the acknowledgment of the local generation of the non-secure warning tone locally by the source phone. ### Claim 4 (depends on 1) The method of claim 1, wherein the step of checking if a generation of a non-secure warning tone locally by the source phone is required comprises the steps of: checking if a warning is required for connecting the security domains of the source phone and the destination phone via a MLS voice gateway; and generating an In-Band non-secure warning tone by the MLS voice gateway. ### Claim 5 (depends on 4) The method of claim 4, further comprising the step of: generating an in-band remote security domain warning by the MLS voice gateway. ### Claim 6 A Multi-Level Secure (MLS) voice gateway for establishing a call between a source phone and a destination phone over a packet-switched network comprising: means for receiving a call attempt from the source phone to the destination phone; means for checking if a connection of security domains of the source phone and the destination phone via the MLS voice gateway is allowed; means for checking if a generation of a non-secure warning tone locally by the source phone is required; means for receiving an acknowledgement of a local generation of the non-secure warning tone by the source phone; and means for establishing a call from the source phone to the destination phone when the acknowledgement of the local generation of the non-secure warning tone by the source phone is received. ### Claim 7 (depends on 6) The MLS voice gateway of claim 6, wherein the means for checking if a connection of the security domains of the source phone and the destination phone via a MLS voice gateway is allowed are further adapted to check if the security domains of the source phone and the destination phone are compatible, and allow the call attempt based on compatibility of the security domains of the source phone and the destination phone. ### Claim 8 (depends on 6) The MLS voice gateway of claim 6, wherein the means for checking if a generation of a non-secure warning tone locally by the source phone is required are further adapted to check if a warning is required for connecting the security domains of the source phone and the destination phone via a MLS voice gateway, and signal to the source phone that the local generation of the non-secure warning tone is required and wait for the acknowledgment of the local generation of the non-secure warning tone locally by the source phone. ### Claim 9 (depends on 6) The MLS voice gateway of claim 6, wherein the means for checking if a generation of a non-secure warning tone locally by the source phone is required are further adapted to check if a warning is required for connecting the security domains of the source phone and the destination phone via a MLS voice gateway, and generate an In-Band non-secure warning tone by the MLS voice gateway. ### Claim 10 (depends on 6) The MLS voice gateway of claim 6, wherein the means for checking if a generation of a non-secure warning tone locally by the source phone is required are further adapted to generate an in-band remote security domain warning by the MLS voice gateway. ### Claim 11 A non-transitory computer-readable medium including processor executable instructions, which when executed by a processor, causes the processor to: receive a call attempt from a source phone to a destination phone; check if a connection of security domains of the source phone and the destination phone via a Multi-Level Secure (MLS) voice gateway is allowed; check if a generation of a non-secure warning tone locally by the source phone is required; receive an acknowledgement of a local generation of the non-secure warning tone by the source phone; and establish a call from the source phone to the destination phone. ### Claim 12 (depends on 11) The non-transitory computer-readable medium of claim 11, wherein the processor executable instructions for checking if the connection of the security domains of the source phone and the destination phone via a MLS voice gateway is allowed cause the processor to: check if the security domains of the source phone and the destination phone are compatible; and allow the call attempt based on compatibility of the security domains of the source phone and the destination phone. ### Claim 13 (depends on 11) The non-transitory computer-readable medium of claim 11, wherein the processor executable instructions for checking if a generation of a non-secure warning tone locally by the source phone is required cause the processor to: check if a warning is required for connecting the security domains of the source phone and the destination phone via a MLS voice gateway; and signal to the source phone that the local generation of the non-secure warning tone is required and wait for the acknowledgment of the local generation of the non-secure warning tone locally by the source phone. ### Claim 14 (depends on 11) The non-transitory computer-readable medium of claim 11, wherein the processor executable instructions for checking if a generation of a non-secure warning tone locally by the source phone is required cause the processor to: check if a warning is required for connecting the security domains of the source phone and the destination phone via a MLS voice gateway; and generate an In-Band non-secure warning tone by the MLS voice gateway. ### Claim 15 (depends on 11) The non-transitory computer-readable medium of claim 11, wherein the processor executable instructions further cause the processor to: generate an in-band remote security domain warning by the MLS voice gateway.