EC25 USB connection overload and do not send all data

IoT Modules LTE Standard Module
1

Hello,
my modem is AT+QGMR EC25EUXGAR08A11M1G_20.003.20.003
I am using NXP micro as host ( Full speed) to connect to this modem.
I create TCP socket with AT commands and send and receive data. All is good with small amount of data (1Kbyte). When I send more data like 1Mbyte device do not send all the data. Internet speed is very slow. (64 kbit). I belive I am overloading internal buffer of EC25. For UART I am using CTS and it is working OK. The questions is: What mechanisim is need to be used when I use USB communication not to overload EC25? Is EC25 will send NAK when internal buffer is full?

Regards,
Stefan

2

Hi @Stefan_Nikolov ，
The length range of data sent by TCP is 0-1460 bytes.

3

I am using socket communication in transparent mode “AT+QIOPEN=1,0,“TCP”,“220.180.239.212”,8009,0,1” Why I need to care about TCP size?
I am transmitting even more than 1 Mbyte. The problem is EC25 continue to receive data even not to able to transmit them. In socket TCP transparent mode. Again my question is: What mechanism needs to be used when I use USB communication not to overload EC25? Is EC25 will send NAK when internal buffer is full?