SimCom SIM7600 Series Installation instructions

SIM7500_SIM7600_SIM7800 Series_SSL_AT
Command Manual_V1.00
Shanghai SIMCom Wireless Solutions Ltd.
Building A, SIM Technology Building, No.633, Jinzhong Road
Changning District 200335
Tel:[phone]
[e-mail]
www.simcom.com
LTE Module

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Document Title: SIM7500_SIM7600_SIM7800 Series_SSL_
AT Command
Manual
Version: 1.00
Date: 2018-10-12
Status: Release
Document ID: SIM7500_SIM7600_SIM7800 Series_SSL_AT Command
Manual_V1.00
General Notes
SIMCom offers this information as a service to its customers, to support application and engineering efforts that
use the products designed by SIMCom. The information provided is based upon requirements specifically
provided to SIMCom by the customers. SIMCom has not undertaken any independent search for additional
relevant information, including any information that may be in the customer’s possession. Furthermore, system
validation of this product designed by SIMCom within a larger electronic system remains the responsibility of the
customer or the customer’s system integrator. All specifications supplied herein are subject to change.
Copyright
This document contains proprietary technical information which is the property of SIMCom Limited., copying of
this document and giving it to others and the using or communication of the contents thereof, are forbidden
without express authority. Offenders are liable to the payment of damages. All rights reserved in the event of grant
of a patent or the registration of a utility model or design. All specification supplied herein are subject to change
without notice at any time.
Copyright © Shanghai SIMCom Wireless Solutions Ltd. 2018

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Version History
Version Date Chapter What is new
V1.00 2018-09-28 New version

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Contents
Version History ................................................................................................................................................ 2
Contents............................................................................................................................................................ 3
1Introduction.............................................................................................................................................. 4
1.1 The SSL Context Management AT Commands ........................................................................................... 4
1.2 The process of Using SSL AT Commands................................................................................................... 4
2 Description of AT Command ....................................................................................................................... 5
2.1 SSL Context Management AT ..................................................................................................................... 5
2.1.1 AT+CSSLCFG Configure the SSL Context................................................................................... 5
2.1.2 AT+CCERTDOWN Download certificate into the module........................................................... 9
2.1.3 AT+CCERTLIST List certificates.................................................................................................. 9
2.1.4 AT+CCERTDELE Delete certificates.......................................................................................... 10
2.2 SSL Services AT ........................................................................................................................................ 10
2.2.1 AT+CCHSET Configure the report mode of sending and receiving data .................................... 10
2.2.2 AT+CCHMODE Configure the mode of sending and receiving data...........................................11
2.2.3 AT+CCHSTART Start SSL service.............................................................................................. 12
2.2.4 AT+CCHSTOP Stop SSL service ................................................................................................ 13
2.2.5 AT+CCHADDR Get the IPv4 address......................................................................................... 13
2.2.6 AT+CCHSSLCFG Set the SSL context ....................................................................................... 13
2.2.7 AT+CCHOPEN Connect to server............................................................................................... 14
2.2.8 AT+CCHCLOSE Disconnect from server ................................................................................... 15
2.2.9 AT+CCHSEND Send data to server ............................................................................................ 16
2.2.10 AT+CCHRECV Read the cached data that received from the server ........................................ 17
2.3 Command result codes and unsolicited codes ........................................................................................... 18
2.3.1 Command result <err> codes.......................................................................................................... 18
2.3.2 Unsolicited result codes.................................................................................................................. 19
3 Example....................................................................................................................................................... 19
3.1 Access to TCP server ................................................................................................................................. 20
3.2 Access to SSL/TLS server (not verify server and client)........................................................................... 22
3.3 Access to SSL/TLS server (only verify the server) ................................................................................... 24
3.4 Access to SSL/TLS server (verify server and client)................................................................................. 26
3.5 Access to SSL/TLS server (only verify the client) .................................................................................... 28
3.6 Access to SSL/TLS server in transparent mode......................................................................................... 31
3.7 Download certificate into module.............................................................................................................. 32
This document is a reference guide to all the AT commands defined for SSL. Through these SSL AT commands,
you can communicate with a TCP or SSL server.

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1Introduction
1.1 The SSL Context Management AT Commands
Step 1: Configure SSL version by AT+CSSLCFG=“sslversion”,<ssl_ctx_index>,<sslversion>.
Step 2: Configure SSL authentication mode by AT+CSSLCFG=“authmode”,<ssl_ctx_index>, <authmode>.
Step 3: Configure the flag of ignore local time by
AT+CSSLCFG=“ignorlocaltime”,<ssl_ctx_index>,<ignoreltime>.
Step 4: Configure the max time in SSL negotiation stage by
AT+CSSLCFG=“negotiatetime”,<ssl_ctx_index>,<negotiatetime>.
Step 5: Configure the server root CA by AT+CSSLCFG=“cacert”,<ssl_ctx_index>,<ca_file>.
Step 6: Configure the client certificate by AT+CSSLCFG=“clientcert”,<ssl_ctx_index>,<clientcert_file>.
Step 7: Configure the client key by AT+CSSLCFG=“clientkey”,<ssl_ctx_index>,<clientkey_file>.
Step 8: Download the certificate into the module by AT+CCERTDOWN.
Step 9: Delete the certificate from the module by AT+CCERTDELE.
Step 10: List the certificates by AT+CCERTLIST.
1.2 The process of Using SSL AT Commands
Step 1: Ensure GPRS network is available before performing SSL related operations.
Step 2: Configure the parameter of PDP context by AT+CGDCONT.
Step 3: Activate the PDP context to start SSL service by AT+CCHSTART.
Step 4: Configure SSL context by AT+CSSLCFG (if connect to SSL/TLS server).
Step 5: Set the SSL context used in SSL connection by AT+CCHSSLCFG (if connect to SSL/TLS server).
Step 6: Connect to the server by AT+CCHOPEN.
Step 7: Send data to the server by AT+CCHSEND.
Step 8: Receive data from server by AT+CCHRECV in manual receive mode.
Step 9: Disconnect from the server by AT+CCHCLOSE.
Step 10: Deactivate the PDP context to stop SSL service by AT+CCHSTOP.
Note:

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2 Description of AT Command
2.1 SSL Context Management AT
2.1.1 AT+CSSLCFG Configure the SSL Context
AT+CSSLCFG Configure the SSL Context
Test Command
AT+CSSLCFG=?
Response
+CSSLCFG: "sslversion",(0-9),(0-4)
+CSSLCFG: "authmode",(0-9),(0-3)
+CSSLCFG: "ignorelocaltime",(0-9),(0,1)
+CSSLCFG: "negotiatetime",(0-9),(10-300)
+CSSLCFG: "cacert",(0-9),(5-128)
+CSSLCFG: "clientcert",(0-9),(5-128)
+CSSLCFG: "clientkey",(0-9),(5-128)
OK
Read Command
AT+CSSLCFG?
Response
+CSSLCFG:
0,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
1,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
2,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
3,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
4,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
5,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>

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+CSSLCFG:
6,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
7,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
8,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
+CSSLCFG:
9,<sslversion>,<authmode>,<ignoreltime>,<negotiatetime>,<
ca_file>,<clientcert_file>,<clientkey_file>
OK
Write Command
/*Query the configuration of the specified
SSL context*/
AT+CSSLCFG=<ssl_ctx_index>
Response
+CSSLCFG:
<ssl_ctxindex>,<sslversion>,<authmode>,<ignoreltime>,<ne
gotiatetime>,<ca_file>,<clientcert_file>,<clientkey_file>
OK
Write Command
/*Configure the version of the specified SSL
context*/
AT+CSSLCFG="sslversion",<ssl_ctx_in
dex>,<sslversion>
Response
a)If successfully:
OK
b)If failed:
ERROR
Write Command
/*Configure the authentication mode of the
specified SSL context*/
AT+CSSLCFG="authmode",<ssl_ctx_in
dex>,<authmode>
Response
a)If successfully:
OK
b)If failed:
ERROR
Write Command
/*Configure the ignore local time flag of the
specified SSL context*/
AT+CSSLCFG="ignorelocaltime",<ssl_c
tx_index>,<ignoreltime>
Response
a)If successfully:
OK
b)If failed:
ERROR
Write Command
/*Configure the negotiate timeout value of the
specified SSL context*/
AT+CSSLCFG="negotiatetime",<ssl_ctx
Response
a)If successfully:
OK
b)If failed:

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_index>,<negotiatetime> ERROR
Write Command
/*
Configure the server root CA of the
specified SSL context*/
AT+CSSLCFG="cacert",<ssl_ctx_index>
,<ca_file>
Response
a)If successfully:
OK
b)If failed:
ERROR
Write Command
/*
Configure the client certificate of the
specified SSL context*/
AT+CSSLCFG="clientcert",<ssl_ctx_ind
ex>,<clientcert_file>
Response
a)If successfully:
OK
b)If failed:
ERROR
Write Command
/*
Configure the client key of the specified
SSL context*/
AT+CSSLCFG="clientkey",<ssl_ctx_ind
ex>,<clientkey_file>
Response
a)If successfully:
OK
b)If failed:
ERROR
Defined Values
<ssl_ctx_index> The SSL context ID. The range is 0-9.
<sslversion> The SSL version, the default value is 4.
0 – SSL3.0
1 – TLS1.0
2 – TLS1.1
3 – TLS1.2
4 – All
The configured version should be support by server. So you
should use the default value if you can’t confirm the version
which the server supported.
<authmode> The authentication mode, the default value is 0.
0 – no authentication.
1 –server authentication. It needs the root CA of the server.
2 –server and client authentication. It needs the root CA of the
server, the cert and key of the client.
3–client authentication and no server authentication. It needs the
cert and key of the client.
<ignoreltime>
The flag to indicate how to deal with expired certificate, the
default value is 1.
0 – care about time check for certification.
1 – ignore time check for certification
When set the value to 0, it need to set the right current date and
time by AT+CCLK when need SSL certification.

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<negotiatetime> The timeout value u
sed in SSL negotiate stage. The range is
10-300 seconds. The default value is 300.
<ca_file>
The root CA file name of SSL context. The file name must have
type like “.pem” or “.der”.The length of filename is from 5 to
128 bytes.
If the filename contains non-
ASCII characters, the file path
parameter should contain a prefix of {non-
ascii} and the
quotation mark (The string in the quotation mark should be
hexadecimal of the filename’s UTF8 code).
There are two ways to download certificate files to module:
1. By AT+CCERTDOWN.
2. By FTPS or HTTPS commands. Please refer to:
SIM7500_SIM7600_SIM7800 Series_FTPS_AT Command
Manual
and SIM7500_SIM7600_SIM7800 Series_HTTP_AT
Command Manual
<clientcert_file> The client cert file name of SSL context. The file name must
have type like “.pem” or “.der”.The length of filename is from 5
to 128 bytes.
If the filename contains non-
ASCII characters, the file path
parameter should contain a prefix of {non-
ascii} and the
quotation mark (The string in the quotation mark should be
hexadecimal of the filename’s UTF8 code).
There are two ways to download certificate files to module:
1. By AT+CCERTDOWN.
2. By FTPS or HTTPS commands. Please refer to:
SIM7500_SIM7600_SIM7800 Series_FTPS_AT Command
Manual and SIM7500_SIM7600_SIM7800 Series_HTTP_AT
Command Manual
<clientkey_file>
The client key file name of SSL context. The file name must
have type like “.pem” or “.der”.The length of filename is from 5
to 128 bytes.
If the filename contains non-
ASCII characters, the file path
parameter should contain a prefix of {non-
ascii} and the
quotation mark (The string in the quotation mark should be
hexadecimal of the filename’s UTF8 code).
There are two ways to download certificate files to module:
1. By AT+CCERTDOWN.
2. By FTPS or HTTPS commands. Please refer to:
SIM7500_SIM7600_SIM7800 Series_FTPS_AT Command
Manual and SIM7500_SIM7600_SIM7800 Series_HTTP_AT

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Command Manual
2.1.2 AT+CCERTDOWN Download certificate into the module
AT+CCERTDOWN Download certificate into the module
Test Command
AT+CCERTDOWN=?
Response
+CCERTDOWN: (5-128),(1-10240)
OK
Write Command
AT+CCERTDOWN=<filename>,<len>
Response
a)If it can be download:
>
<input data here>
b)If failed:
ERROR
Defined Values
<filename> The name of the certificate/key file. The file name must have
type like “.pem” or “.der”. The length of filename is from 5 to
128 bytes.
If the filename contains non-
ASCII characters, the file path
parameter should contain a prefix of {non-
ascii} and the
quotation mark (The string in the quota
tion mark should be
hexadecimal of the filename’s UTF8 code).
For example: If you want to download a file with name “中
华.pem”, you should convert the “中华.pem” to UTF8 coding
(&#x4E2D;&#x534E;.pem), then input the hexadecimal
(262378344532443B262378353334453
B2E70656D) of UTF8
coding.
<len>
The length of the file data to send. The range is from 1 to 10240
bytes.
2.1.3 AT+CCERTLIST List certificates
AT+CCERTLIST List certificates
Execute Command
AT+CCERTLIST
Response
[+CCERTLIST:<file_name>
[+CCERTLIST:<file_name>]
…

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<CR><LF>]
OK
Defined Values
<filename>
The certificate/key files which has been downloaded to the
module.
If the filename contains non-ASCII characters, it will show the
non-ASCII characters as UTF8 code.
2.1.4 AT+CCERTDELE Delete certificates
AT+CCERTDELE Delete certificate from the module
Write Command
AT+CCERTDELE=<filename>
Response
a)If delete successfully:
OK
b)If failed:
ERROR
Defined Values
<filename>
The name of the certificate/key file. The file name must have
type like “.pem” or “.der”. The length of filename is from 5 to
128 bytes.
If the filename contains non-
ASCII characters, the file path
parameter should contain a prefix of {non-
ascii} and the
quotation mark (The string in the quotation mark should be
hexadecimal of the filename’s UTF8 code).
For example: If you want to download a file with name “中
华.pem”, you should convert the “中华.pem” to UTF8 coding
(&#x4E2D;&#x534E;.pem), then input the hexadecimal
(262378344532443B262378353334453B2E70656D) of UTF8
coding.
2.2 SSL Services AT
2.2.1 AT+CCHSET Configure the report mode of sending and receiving data
AT+CCHSET is used to configure the mode of sending and receiving data. It must be called before
AT+CCHSTART.

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AT+CCHSET Configure the report mode of sending and receiving
Test Command
AT+CCHSET=?
Response
+CCHSET: (0,1),(0,1)
OK
Read Command
AT+CCHSET?
Response
+CCHSET: <report_send_result>,<recv_mode>
OK
Write Command
AT+CCHSET=<report_send_result>[,<re
cv_mode>]
Response
a)If successfully:
OK
b)If failed:
ERROR
Defined Values
<report_send_result> Whether to report result of CCHSEND, the default value is 0:
0 – No.
1–Yes .
Module will report +CCHSEND: <session_id>,<err> to
MCU when complete sending data.
<recv_mode> The receiving mode:
0 – Output the data to MCU whenever received data.
1 –
Module caches the received data and notifies MCU with
+CCHEVENT: <session_id>, RECV EVENT.
MCU can use AT+CCHRECV to receive the cached data (only
in manual receiving mode).
2.2.2 AT+CCHMODE Configure the mode of sending and receiving data
AT+CCHMODE is used to elect transparent mode (data mode) or non-transparent mode (command mode). The
default mode is non-transparent mode. This AT command must be called before calling AT+CCHSTART.
NOTE: There is only one session in the transparent mode, it’s the first session.
AT+CCHMODE Configure the mode of sending and receiving
Test Command
AT+CCHMODE=?
Response
+CCHMODE: (0,1)
OK
Read Command
AT+CCHMODE?
Response
+CCHMODE: <mode>

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OK
Write Command
AT+CCHMODE=<mode>
Response
a)If successfully:
OK
b)If failed:
ERROR
Defined Values
<mode> The mode value:
0–Normal.
1 –Transparent mode
The default value is 0.
2.2.3 AT+CCHSTART Start SSL service
AT+CCHSTART is used to start SSL service by activating PDP context. You must execute AT+CCHSTART
before any other SSL related operations.
AT+CCHSTART Start SSL service
Execute Command
AT+CCHSTART
Response
a)If start SSL service successfully:
OK
+CCHSTART: 0
b)If start SSL service successfully:
+CCHSTART: 0
OK
c)If failed:
ERROR
d)If failed:
ERROR
+CCHSTART: <err>
Maximum Response Time 120000ms
Defined Values
<err> The result code, please refer to chapter 2.3.1

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2.2.4 AT+CCHSTOP Stop SSL service
AT+CCHSTOP is used to stop SSL service.
AT+CCHSTOP STOP SSL service
Execute Command
AT+CCHSTOP
Response
a)If stop SSL service successfully:
+CCHSTOP: 0
OK
b)If stop SSL service successfully:
OK
+CCHSTOP: 0
c)If failed:
ERROR
Defined Values
<err> The result code, please refer to chapter 2.3.1
2.2.5 AT+CCHADDR Get the IPv4 address
AT+CCHADDR is used to get the IPv4 address after calling AT+CCHSTART.
AT+CCHSADDR Get the IPv4 address
Execute Command
AT+CCHADDR
Response
+CCHADDR: < ip_address>
OK
Defined Values
<ip_address> A string
parameter that identifies the IPv4 address after PDP
activated.
2.2.6 AT+CCHSSLCFG Set the SSL context
AT+CCHSSLCFG is used to set the SSL context which to be used in the SSL connection. It must be called
before AT+CCHOPEN and after AT+CCHSTART.The setting will be cleared after the CCHOPEN operation is
finished.

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NOTE: If you don’t set the SSL context by this command before connecting to SSL/TLS server by
AT+CCHOPEN, the CCHOPEN operation will use the SSL context as same as index <session_id> (the 1st
parameter of AT+CCHOPEN) when connecting to the server.
AT+CCHSSLCFG Set the SSL context
Test Command
AT+CCHSSLCFG=?
Response
+ CCHSSLCFG: (0,1),(0-9)
OK
Read Command
AT+CCHSSLCFG?
Response
+CCHSSLCFG: <session_id>,[<ssl_ctx_index >]
+CCHSSLCFG: <session_id>,[<ssl_ctx_index >]
OK
Write Command
AT+CCHSSLCFG=<session_id>,<ssl_ctx
_index>
Response
a)If successfully:
OK
b)If failed:
ERROR
Defined Values
<session_id>
The session_id to operate. It’s from 0 to 1.
<ssl_ctx_index>
The SSL context ID
which will be used in the SSL connection.
Refer to the <ssl_ctx_index> of AT+CSSLCFG.
2.2.7 AT+CCHOPEN Connect to server
AT + CCHOPEN is used to connect to the server.
NOTE: If you don’t set the SSL context by AT+CCHSSLCFG before connecting a SSL/TLS server by
AT+CCHOPEN, it will use the <session_id>( the 1’st parameter of AT+CCCHOPEN) SSL context when
connecting to the server.
AT+CCHOPEN Connect to server
Test Command
AT+CCHOPEN=?
Response
+CCHOPEN: (0,1),”ADDRESS”,
(1-65535)[,(1-2)[,(1-65535)]]
OK
Write Command
AT+CCHOPEN=<session_id>, ”<host>”,
<port>[<client_type>,[<bind_port>]]
Response
a)If connect successfully：
+CCHOPEN: <session_id>,0

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OK
b)If connect successfully：
OK
+CCHOPEN: <session_id>,0
c)If connect successfully in transparent mode：
CONNECT [<text>]
d)If failed：
OK
+CCHOPEN: <session_id>,<err>
e)If failed:
ERROR
f)If failed in transparent mode:
CONNECT FAIL
Defined Values
<session_id> The session index to operate. It’s from 0 to 1.
<host> The server address, maximum length is 256 bytes.
<port>
The server port which to be connected, the range is from 1 to
65535.
<client_type>
The type of client:
1–TCP client.
2 –SSL/TLS client.
<bind_port> The local port for channel, the range is from 1 to 65535.
<text>
CONNECT result code string; the string formats please refer
ATX /AT \V/AT&E command.
<err> The result code: 0 is success. Other values are failure. Please
refer to chapter 2.3.1
2.2.8 AT+CCHCLOSE Disconnect from server
AT+CCHCLOSE is used to disconnect from the server.
AT+CCHCLOSE Disconnect from the Server
Write Command
AT+CCHCLOSE=<session_id>
Response
a)If successfully：
+CCHCLOSE: <session_id>,0
OK

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b)If successfully：
OK
+CCHCLOSE: <session_id>,0
c)If successfully in transparent mode：
OK
CLOSED
d)If failed:
ERROR
Defined Values
<session_id> The session index to operate. It’s from 0 to 1.
<err> The result code: 0 is success. Other values are failure. Please
refer to chapter 2.3.1.
2.2.9 AT+CCHSEND Send data to server
You can use AT+CCHSEND to send data to server.
AT+CCHSEND Send Data
Test Command
AT+CCHSEND=?
Response:
+CCHSEND: (0,1),(1-2048)
OK
Read Command
AT+CCHSEND?
Response:
+CCHSEND: 0,<unsent_len_0>,1,<unsent_len_1>
OK
Write Command
AT+CCHSEND=<session_id>,<len>
Response
a)if parameter is right:
>
<input data here>
When the total size of the inputted data reaches <len>,
TA will
report the following code. Otherwise, the serial port will be

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blocked.
OK
b)If parameter is wrong or other errors occur:
ERROR
Defined Values
<session_id> The session_id to operate. It’s from 0 to 1.
<len> The length of data to send. Its range is from 1 to 2048 bytes.
<unsent_len_0> The data of connection 0 cached in sending buffer which is waiting
to be sent.
<unsent_len_1> The data of connection 1 cached in sending buffer which is waiting
to be sent.
2.2.10 AT+CCHRECV Read the cached data that received from the server
You can use AT+CCHRECV to read the cached data which received from the server.
AT+CCHRECV Receive the cached data that received from server
Read Command
AT+CCHRECV?
Response
+CCHRECV: LEN,<cache_len_0>,<cache_len_1>
OK
Write Command
AT+CCHRECV=<session_id>[,<max_rec
v_len>]
Response
a)if parameter is right and there are cached data:
OK
[+CCHRECV: DATA, <session_id>,<len>
…
+CCHRECV: DATA, <session_id>,<len>
…]
+CCHRECV: <session_id>,<err>
b) if parameter is not right or any other error occurs:
+CCHRECV: <session_id>,<err>
ERROR
Defined Values
<session_id> The session_id to operate. It’s from 0 to 1.
<max_recv_len>
Maximum bytes of data to receive in the current AT+CCHRECV

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calling. It will read all the received data when the value is greater
than the length of RX data cached for session <session_id>.
0 means the maximum bytes to receive is 2048 bytes. (But, when
2048 is greater than the length of RX data cached for session
<session_id>, 0 means the length of RX data cached for session
<session_id>).
The default value is the length of RX d
ata cached for session
<session_id>.
It will be not allowed when there is no data in the cache.
<cache_len_0>
The length of RX data cached for connection 0.
<cache_len_1> The length of RX data cached for connection 1.
<len> The length of data followed.
<err> The result code: 0 is success. Other values are failure. Please refer
to chapter 2.3.1.
2.3 Command result codes and unsolicited codes
2.3.1 Command result <err> codes
Result codes
0 Operation succeeded
1Alerting state(reserved)
2Unknown error
3Busy
4 Peer closed
5Operation timeout
6Transfer failed
7Memory error
8 Invalid parameter
9Network error
10 Open session error
11 State error
12 Create socket error
13 Get DNS error
14 Connect socket error
15 Handshake error
16 Close socket error
17 Nonet
18 Send data timeout

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SIM7500_SIM7600_SIM7800 Series_SSL_AT Command Manual 19 / 36
19 Not set certificates
2.3.2 Unsolicited result codes
Unsolicited codes
+CCHEVENT: <session_id>,RECV
EVENT
In manual receiving mode, when new data of a connection
arriving to the module, this
unsolicited result code will be
reported to MCU.
+CCH_RECV_CLOSED:
<session_id>,<err>
When receive data occurred any error, this unsolicited result
code will be reported to MCU.
+CCH_PEER_CLOSED: <session_id>
The connection is closed by the server.
3 Example
Before all SSL related operations, we should ensure the following:
a) ensure GPRS network is available:
AT+CSQ
+CSQ: 23,0
OK
AT+CREG?
+CREG: 0,1
OK
AT+CGREG?
+CGREG: 0,1
OK
b) PDP context Enable: