DFS email

FCC ID: LDK7900001

Cover Letter(s)

Download: PDF
FCCID_732176

Dward ATCB From: Dward ATCB [dward@atcb.com] Sent: 11/06/2006 7:12 PM To: Dennis Ward; Lisa Bevington (lbevingt) Cc: Marianne Bosley; William Graff Subject: RE: LDK7900001_ATCB004212 Hi Lisa Here is my concern. WLAN devices have what is know as an “Ad-Hoc” mode. This mode is used when two computers ‘talk’ to each other without going through an access point. Some time called computer to computer mode. The manual (page 40) says that this device has an ad-hoc teleconference mode that is standard. What this means is confusing in terms of the already accepted definition of ad-hoc with 802.11 devices. The manual indicates that even this mode still goes through the system and thus through the access point involved. However, terms are terms and they mean what they mean. If they are to mean something other than what is accepted for the type device, then this needs to be carefully explained so confusion does not come about. For example, if a handset could talk directly to another handset without going through the access point, then on of them would have to have DFS capability so as to be the master. The operational description is of no help and further clouds the issue by stating the handset has a “push-to-talk” mode thus indicating a possibility of hand set to handset use. Again, while this does not obviously look like the case, it does need to be specifically addressed. Consequently, adequate clarification on the operating conditions of the device in this “ad hoc” mode is needed. Dennis Ward Evaluation Engineer American TCB Certification Resource for the Wireless Industry www.atcb.com 703‐847‐4700 fax 703‐847‐6888 direct ‐ 703‐880‐4841 cell ‐ 209‐769‐8316 NOTICE: This E‐Mail message and any attachment may contain privileged or company proprietary information. If you received this message in error, please return to the sender. From: Dward ATCB [mailto:dward@atcb.com] Sent: 11/06/2006 6:46 PM To: 'Lisa Bevington (lbevingt)' Cc: 'marianneb@atcb.com'; 'William Graff' Subject: RE: LDK7900001_ATCB004212 Hi Lisa If the client device does not have DFS capability (other than to vacate the channel when told to by the master etc) then a TCB can do this. It appears as if this is what the device does, but there is no clear evidence in the documentation that this device does not have DFS capabilities (i.e. listens to radar and reacts appropriately on its own). A device with ad hoc mode for example would be this type device. If the device does have DFS detection the it really does not matter where it was tested, the FCC will require a sample. 11/06/06

Again, I do not think this is the case, but I need to make absolutely sure. Thanks Dennis Ward Evaluation Engineer American TCB Certification Resource for the Wireless Industry www.atcb.com 703‐847‐4700 fax 703‐847‐6888 direct ‐ 703‐880‐4841 cell ‐ 209‐769‐8316 NOTICE: This E‐Mail message and any attachment may contain privileged or company proprietary information. If you received this message in error, please return to the sender. From: Lisa Bevington (lbevingt) [mailto:lbevingt@cisco.com] Sent: 11/06/2006 5:24 PM To: Dward ATCB Cc: marianneb@atcb.com; William Graff Subject: RE: LDK7900001_ATCB004212 Hi Dennis, I checked to make sure and I uploaded the DFS test Report. Let me know if you need me to upload it again. I am checking with the compliance team to get you the answers to your questions. Can you clarify for me.....Does FCC require to have a unit sent to them even though we did the DFS testing at an outside Lab? Thanks Lisa From: Dward ATCB [mailto:dward@atcb.com] Sent: Monday, 06 November, 2006 2:45 PM To: Lisa Bevington (lbevingt) Cc: marianneb@atcb.com; 'William Graff' Subject: RE: LDK7900001_ATCB004212 Hi Lisa Maybe a more appropriate question would be – is this strictly a slave device or does it actually have a mode that requires it to have DFS testing??? Thanks Dennis Ward Evaluation Engineer American TCB Certification Resource for the Wireless Industry www.atcb.com 11/06/06

703‐847‐4700 fax 703‐847‐6888 direct ‐ 703‐880‐4841 cell ‐ 209‐769‐8316 NOTICE: This E‐Mail message and any attachment may contain privileged or company proprietary information. If you received this message in error, please return to the sender. _____________________________________________ From: Dward ATCB [mailto:dward@atcb.com] Sent: 11/06/2006 2:31 PM To: 'Lisa Bevington (lbevingt)' Cc: 'marianneb@atcb.com'; 'William Graff' Subject: LDK7900001_ATCB004212 Hi Lisa Before I get too far into this review, does this actually operate in the 5250 to 5350MHz range. If it does the it must be sent to the FCC as it requires DFS testing. Please note that the FCC will also require the actual device to be sent to them for testing. Thanks Dennis Ward Evaluation Engineer American TCB Certification Resource for the Wireless Industry www.atcb.com 703‐847‐4700 fax 703‐847‐6888 direct ‐ 703‐880‐4841 cell ‐ 209‐769‐8316 NOTICE: This E‐Mail message and any attachment may contain privileged or company proprietary information. If you received this message in error, please return to the sender. 11/06/06

From: Lisa Bevington (lbevingt) [mailto:lbevingt@cisco.com] Sent: 11/07/2006 12:49 PM To: Dward ATCB Cc: marianneb@atcb.com; William Graff; Craig Mullis (cmullis); Phillip Carranco (pcarranc); David Case (davecase) Subject: RE: LDK7900001_ATCB004212 Hi Dennis, Here is the response from Dave Case on the DFS issue: The CP-7921G phone is a client only device that does not do radar detection. It operates as a Client / slave and does not support any ad-hoc transmission modes. The system waits for the AP to tell it what channel it may operate on. Terminology, in 802.11 world the term Ad-hoc means the capability of one client device to directly connect with another client device without going through an Access Point. However in the non 802 world including telecom, ad-hoc basically means capability to perform certain functions from a device such as conference call without having to go through a conference call center. In this case, the user of the phone can set up an ad-hoc conference call without out having to go through a conference center. The phone however is incapable of talking directly to another phone without going through an Access Point. Thanks Lisa From: Dward ATCB [mailto:dward@atcb.com] Sent: Monday, 06 November, 2006 7:12 PM To: 'Dward ATCB'; Lisa Bevington (lbevingt) Cc: marianneb@atcb.com; 'William Graff' Subject: RE: LDK7900001_ATCB004212 Hi Lisa Hate to keep emailing you with so many emails, but this is probably the last one on the DFS issue. Here is my concern. WLAN devices have what is know as an “Ad-Hoc” mode. This mode is used when two computers ‘talk’ to each other without going through an access point. Some time called computer to computer mode. The manual (page 40) says that this device has an ad-hoc teleconference mode that is standard. What this means is confusing in terms of the already accepted definition of ad-hoc with 802.11 devices. The manual indicates that even this mode still goes through the system and thus through the access point involved. However, terms are terms and they mean what they mean. If they are to mean something other than what is accepted for the type device, then this needs to be carefully explained so confusion does not come about. For example, if a handset could talk directly to another handset without going through the access point, then on of them would have to have DFS capability so as to be the master. The operational description is of no help and further

clouds the issue by stating the handset has a “push-to-talk” mode thus indicating a possibility of hand set to handset use. Again, while this does not obviously look like the case, it does need to be specifically addressed. Consequently, adequate clarification on the operating conditions of the device in this “ad hoc” mode is needed. Dennis Ward Evaluation Engineer American TCB Certification Resource for the Wireless Industry www.atcb.com 703‐847‐4700 fax 703‐847‐6888 direct ‐ 703‐880‐4841 cell ‐ 209‐769‐8316 NOTICE: This E‐Mail message and any attachment may contain privileged or company proprietary information. If you received this message in error, please return to the sender. s E‐Mail message and any attachment may contain privileged or company proprietary information. If you received this message in error, please return to the sender.


Document Created: 2006-11-27 15:55:55
Document Modified: 2006-11-27 15:55:55
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