help- how to issue other commands to sim800 while still being connected to mqtt server

[dmsherazi]

If i need to check sms or signal strength while connected to mqtt serevr on sim800 I have to issue escape sequence and this will disconnect me from serevr!

I need to check for incoming calls and sms and at times for signal strength or CREG . I haven't used sim800 a lot for data before so my pardon me if its a silly question!

[pat1]

This library implement sim800 for transparent tcp connection and do other things when transparent is active is not possible.

But after a switch Between Data Mode to Command Mode The manual report:

ATO command can be used to switch the module from command mode to data mode if the
connection is active, and CONNECT will be returned again. 

so you can try :

sim800Client::transparentescape()
.... do somethings
....
sim800Client::transparent()

but the time from transparentescape and transparent cannot exceed :

// MQTT_KEEPALIVE : keepAlive interval in Seconds
#define MQTT_KEEPALIVE 30

in PubSubClient.h Please report here if this works.

There are other modes to do tcp connection with sim800; multi connection mode

Multi Connection
To enable multi connection mode, the command AT+CIPMUX must be set to 1. Be aware
that in the multi connection mode, SIM800 series only supports non-transparent mode. Due to this
matter, the command AT+CIPMODE is invalid under multi connection mode.
In multi connection mode, SIM800 series can work as a TCP/UDP client or a TCP server.
As a client, it can establish 6 connections to remote server in total, both TCP and UDP. 

Multi connection is not implemented in this library.

For other functionality take a look at SIM800 Series_TCPIP_Application

2.2.5
How to handle incoming call and short message in data mode 

[dmsherazi]

Thanks a lot @pat1 for the detailed answer.