how to configure asterisk instant messaging

Question 1

Yes. Asterisk is supporting IM. Please Use Asterisk 11 or higher version. I think you are using old version. I had same problem in asterisk-10. I upgraded to Asterisk to Asterisk-11. Please see below Detail instruction for Asterisk IM.

Write below line in general section of sip.conf file.

[general]

accept_outofcall_message=yes 
outofcall_message_context=dialplan_name
auth_message_requests=yes

Write below lines in extensions.conf file. This is dialplan to send IM.

[dialplan_name]
exten => _.,1,NoOp(SMS receiving dialplan invoked)
exten => _.,n,NoOp(To ${MESSAGE(to)})
exten => _.,n,NoOp(From ${MESSAGE(from)})
exten => _.,n,NoOp(Body ${MESSAGE(body)})
exten => _.,n,AGI(chatplan.php,${MESSAGE(from)})
;exten => _.,n,Set(ACTUALTO=${CUT(MESSAGE(to),@,1)})
;exten => _.,n,ExecIf($["${ACTUALTO}" != "sip:${EXTEN}"]?Set(ACTUALTO=sip:${EXTEN}))
exten => _.,n,MessageSend(${ACTUALTOS},${MESSAGE(from)})
exten => _.,n,NoOp(Send status is ${MESSAGE_SEND_STATUS})
exten => _.,n,GotoIf($["${MESSAGE_SEND_STATUS}" != "SUCCESS"]?sendfailedmsg)
exten => _.,n,Hangup()
;
; Handle failed messaging
exten => _.,n(sendfailedmsg),NoOp(Sending error to user)
exten => _.,n,Set(SRC=${MESSAGE(from)})
exten => _.,n,Set(DST=${MESSAGE(to)})
exten => _.,n,Set(MSG=${MESSAGE(body)}) 
exten => _.,n,Set(MESSAGE(body)="[${STRFTIME(${EPOCH},,%d%m%Y-%H:%M:%S)}] Your message to ${EXTEN} has failed. Sending when available")
exten => _.,n,Set(ME_1=${CUT(MESSAGE(from),<,2)})
exten => _.,n,Set(ACTUALFROM=${CUT(ME_1,@,1)})
exten => _.,n,MessageSend(${ACTUALFROM},ServiceCenter)
exten => _.,n,GotoIf($["${INQUEUE}" != "1"]?startq)
exten => _.,n,Hangup()
;
exten => _.,n(startq),NoOp(Queueing messaging for offline)
exten => _.,n,Set(MSGTIME=${STRFTIME(${EPOCH},,%d%m%Y-%H:%M:%S)})
exten => _.,n,SYSTEM(/var/lib/asterisk/agi-bin/astqueue.sh –SRC ‘${SRC}’ –DST ‘${DST}’ –MSG ‘${MSG}’)
exten => _.,n,Hangup()[app-fakeanswer]
exten => _.,1,NoCDR
exten => _.,n,Set(DESTDEV=${EXTEN})
exten => _.,n,Set(THISDEVSTATE=${DEVICE_STATE(SIP/${DESTDEV})})
exten => _.,n,GotoIf($["${THISDEVSTATE}" = "UNAVAILABLE"]?hang)
exten => _.,n,GotoIf($["${THISDEVSTATE}" = "UNKNOWN"]?hang)
exten => _.,n,Answer
exten => _.,n,Hangup()
exten => _.,n(hang),Hangup()

Add above lines in your respected files. Use Asterisk-11 for IM. I had same problem in older asterisk version. Hope you are using Asterisk-11.

Question 2

After messing a while Asterisk Version 13, got it to work from my celular to another celular. It depends also on the agent doing delivery. if the app or program is not capable of taking the message, there is nothing you can do and you will get this msg:

Unable to create channel of type 'SIP' (cause 58 - Bearer capability not available)

But if the units are capable of messaging then you will get an OK. The best way to test, is first doit on the same unit, you can send and receive a message to yourself. Once you get the msg on your same celular, then you know its working at least in your unit, then you can test in another unit using the same app or program. After you achieve that, then you need to try on a different app or program and unit then debug if does not work.

[MENSAGEIRO]

exten => _.,1,NoOp(SMS receiving dialplan invoked)
exten => _.,n,NoOp(To ${MESSAGE(to)})
exten => _.,n,NoOp(From ${MESSAGE(from)})
exten => _.,n,NoOp(Body ${MESSAGE(body)})
;exten => _.,n,AGI(chatplan.php,${MESSAGE(from)})
exten => _.,n,Set(ACTUALTO=${CUT(MESSAGE(to),@,1)})
exten => _.,n,ExecIf($["${ACTUALTO}" != "sip:${EXTEN}"]?Set(ACTUALTO=sip:${EXTEN}))
exten => _.,n,MessageSend(${ACTUALTO},${MESSAGE(from)})
exten => _.,n,NoOp(Send status is ${MESSAGE_SEND_STATUS})
exten => _.,n,GotoIf($["${MESSAGE_SEND_STATUS}" != "SUCCESS"]?sendfailedmsg)
exten => _.,n,Hangup()
;; Handle failed messaging
exten => _.,n(sendfailedmsg),NoOp(Sending error to user)
exten => _.,n,Set(SRC=${MESSAGE(from)})
exten => _.,n,Set(DST=${MESSAGE(to)})
exten => _.,n,Set(MSG=${MESSAGE(body)})
exten => _.,n,Set(MESSAGE(body)="[${STRFTIME(${EPOCH},,%d%m%Y-%H:%M:%S)}] Sua mensagem para ${EXTEN} falhou. Destinatário não está on-line")
exten => _.,n,Set(ME_1=${CUT(MESSAGE(from),<,2)})
exten => _.,n,Set(ACTUALFROM=${CUT(ME_1,@,1)})
exten => _.,n,MessageSend(${ACTUALFROM},ServiceCenter)
;exten => _.,n,GotoIf($["${INQUEUE}" != "1"]?startq)
exten => _.,n,Hangup()

You need to add those lines in the file extensions.conf and reference in file sip.conf or user.conf using this context called MENSAGEIRO on /etc/asterisk folder.

You wil notice on CLI once you see the msg has gone thru successfully here

 NoOp("Message/ast_msg_queue", "Send status is SUCCESS") in new stack

Credits https://gist.github.com/jugaso/58d76fade445521d7fc15b9c82ee7a50