# API Mode - Sending with an API\_ID of 0x00 results in a receive packet API\_ID of 0x81
**URL:** https://forums.digi.com/t/api-mode-sending-with-an-api-id-of-0x00-results-in-a-receive-packet-api-id-of-0x81/11474
**Category:** XBee - 802.15.4
**Tags:** xbee, api-mode, zigbee-recieve-packe
**Created:** [May 9, 2013, 6:21am UTC](https://forums.digi.com/t/api-mode-sending-with-an-api-id-of-0x00-results-in-a-receive-packet-api-id-of-0x81/11474 "2013-05-09T06:21:55Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Sefi](https://forums.digi.com/u/Sefi)
#### Post date: [May 9, 2013, 6:21am UTC](https://forums.digi.com/t/api-mode-sending-with-an-api-id-of-0x00-results-in-a-receive-packet-api-id-of-0x81/11474/1 "2013-05-09T06:21:55Z")
Series 1 Xbee - In API mode, I send a message to a receiving Xbee as a 64 bit address using API\_ID of 0x00. However the receiving Xbee receives the message with an ID of 0x81 from the sender which is 16 bit Network address. Can anyone tell me what is wrong here. My understanding is that if I use API\_ID of 0x00 then the receiver will get a packet with an ID of 0x80 and if the sending API\_ID is 0x01 then the receiver will get a packet with an id of 0x81. But this is not happening. many thanks for your help.
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### Author:  [@jeremy](https://forums.digi.com/u/jeremy)
#### Post date: [May 10, 2013, 2:44pm UTC](https://forums.digi.com/t/api-mode-sending-with-an-api-id-of-0x00-results-in-a-receive-packet-api-id-of-0x81/11474/2 "2013-05-10T14:44:14Z")
If you configure the receiving radio with a normal MY address the unicast packets you send will transmit to the correct 16 or 64 bit address you specify. You will get a 16 bit 0x81 response out as it will default back to a 16 bit addressing mode no matter the send mode.
If you configure the receiving radio and/or the transmitting radio with a MY address of FFFF packets you send will transmit only with a 64 bit address and you will start getting 0x80 64 bit recieve packets.
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### Author:  [@Sefi](https://forums.digi.com/u/Sefi)
#### Post date: [May 10, 2013, 3:36pm UTC](https://forums.digi.com/t/api-mode-sending-with-an-api-id-of-0x00-results-in-a-receive-packet-api-id-of-0x81/11474/3 "2013-05-10T15:36:20Z")
Thank you Jeremy. Its all clear now.
many thanks.