# End to End TCP Connection by HL8548

**URL:** <https://forum.sierrawireless.com/t/end-to-end-tcp-connection-by-hl8548/7810>\
**Category:** Legacy HL Series\
**Created:** [March 9, 2015, 3:33pm UTC](https://forum.sierrawireless.com/t/end-to-end-tcp-connection-by-hl8548/7810 "2015-03-09T15:33:24Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![uwek](https://avatars.discourse-cdn.com/v4/letter/u/47e85d/32.png) [@uwek](https://forum.sierrawireless.com/u/uwek)\
**Post date:** [March 9, 2015, 3:33pm UTC](https://forum.sierrawireless.com/t/end-to-end-tcp-connection-by-hl8548/7810/1 "2015-03-09T15:33:24Z")

</div>

I would like use the above Connection.  
I use the AT Command Interface Guide point 20.6.4 without AT&K3  
By the Command:  
AT+KCNXCFG=1,“GPRS”,“zz.xxx.yyyyy”,“log”,“pin”,“IPV4”,“0.0.0.0”,“0.0.0.0”,“0.0.0.0”  
AT+KTCPCFG=1,0,“111.80.90.100”,1000  
AT+KTCPSTART=1  
I get  
+CME ERROR: 923 which meen “Error due to invalid state of terminate port data mode”  
I do not understand.

---

<div class="post-metadata">

**Author:** ![Rex\_alex](https://avatars.discourse-cdn.com/v4/letter/r/73ab20/32.png) [@Rex\_alex](https://forum.sierrawireless.com/u/Rex_alex)\
**Post date:** [March 11, 2015, 10:07am UTC](https://forum.sierrawireless.com/t/end-to-end-tcp-connection-by-hl8548/7810/2 "2015-03-11T10:07:15Z")

</div>

Hi,  
which FW version are you using? Can you try with the latest FW version?

Regards,  
Alex

---

<div class="post-metadata">

**Author:** ![uwek](https://avatars.discourse-cdn.com/v4/letter/u/47e85d/32.png) [@uwek](https://forum.sierrawireless.com/u/uwek)\
**Post date:** [March 11, 2015, 1:25pm UTC](https://forum.sierrawireless.com/t/end-to-end-tcp-connection-by-hl8548/7810/3 "2015-03-11T13:25:39Z")

</div>

Hi Alex,  
the modul use SW BHL85xx.5.5.4.0.201409051956.x6250\_1  
My problem is solved.  
I put in this command “AT+KTCPCNX=1” in front of “AT+KTCPSTART=1” so I get a “CONNECT” after Start.  
The next problem is to switch off the commandmode.  
I put in “+++” like in the “AT Commands Interface Guide” but I do not get a OK from module.

Best Regards Uwe

---

<div class="post-metadata">

**Author:** ![krima919](https://avatars.discourse-cdn.com/v4/letter/k/94ad74/32.png) [@krima919](https://forum.sierrawireless.com/u/krima919)\
**Post date:** [March 12, 2015, 9:28am UTC](https://forum.sierrawireless.com/t/end-to-end-tcp-connection-by-hl8548/7810/4 "2015-03-12T09:28:42Z")

</div>

There must be a guard period before and after +++, I think the guard period should be at least 1s.

It should also be possible to use the DTR pin to exit data mode, but I think you need to update the FW because I think there was some issues with that in the early FW releases.

---

<div class="post-metadata">

**Author:** ![uwek](https://avatars.discourse-cdn.com/v4/letter/u/47e85d/32.png) [@uwek](https://forum.sierrawireless.com/u/uwek)\
**Post date:** [April 14, 2015, 1:47pm UTC](https://forum.sierrawireless.com/t/end-to-end-tcp-connection-by-hl8548/7810/5 "2015-04-14T13:47:15Z")

</div>

Thanks for the answer,

my next issue is to close the connection.

I get following:  
GSM: AT+KTCPCLOSE=1,1  
GSM: AT+KTCPDEL=1  
: 1,8 +KTCP\_DATA: 1,8 +KTCP\_DATA: 1,8 +KTCP\_DATA: 1,8 +CME ERROR: 922  
GSM: AT+KTCPDEL=1  
+CME ERROR: 922  
MAIN\_STATE\_START\_SLEEP  
GSM: AT+KTCPDEL=1  
+CME ERROR: 922

It looks like if data in the pipe. How I have to pick up the data by an end to end connection.  
How has an answer.

Uwe