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7920 with AP 1010

secoffey
Level 1
Level 1

To avoid one way communication cisco recommend having same power on both phone and AP.

Ok but what is the recommandation when AP and phone does not have same antenna gain.

My infrastucture is based on WiSM controller with AP 1010. DTPC is enabled on controller so 20mW is send to 7920. But AP 1010 has 5.5dBi antenna gain and 7920 2.2dBi.

Should I disable DTPC on controller and raise power to 50mW on 7920 to avoid one-way communication

2 Replies 2

ctmcse
Level 1
Level 1

"A high-gain antenna on an access point will receive a signal from a 5-mW client from a greater distance than a low-gain antenna. It is the difference in transmitter power and receiver sensitivity that matters because the gain of an antenna is reciprocal. To verify the cell coverage edge of ?67 dBm while the client is actively sending and receiving voice size packets, check the access point?s Station Information and Status page for a dBm value of ?67 dBm or higher." Site Survey Guide for Deploying Cisco 7920 IP Phones

The 1010 antenna will determine the cell size. As it will be able to pull in the weaker signal. An issue may arise from the RSSI value in your cells, the 7920 needs a minimum of -67dBm RSSI.

HTH,

Chuck Taylor

migilles
Cisco Employee
Cisco Employee

The 7920 has 0dBi antenna. Yes in Airespace controller, can only DTPC, but not set client power per AP. It will send the current configured ap power to the client. In the US, 1 is the highest which is 100mw. Going down from there the tx power is cut in half (2=50, 3=25, 4=12, etc.). Most of these powers the 7920 will not support (only 1,5,20,50,100), so will bump up to the next highest tx power anyways, except for 100mw and 50mw. Hopefully a voice cell will not be that large unless is for a warehous or outdoor.

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