The BrandMeister Germany team has implemented some nice features.
They coded some 'SMS servicenumbers', these are services you can address via BM SMS.

Their documentation can be found in the BM262 BrandMeister Wiki

I made an English translation of te SMSC service number.

262995 - SMSC

English translation by ON7LDS

Preface

• set the correct Brand for your transceiver in your BrandMeister SelfCare
• all commands should be sent as a private call to the 262995
• the commands are case-insensitive
• there should be only one space between query parts
• information in <brackets> are placeholders for parameters, '<' and '>' should not be sent
• some Chinese devices (eg Anytone or RT3) unfortunately can not receive long text messages and may show only parts of the message or ignore the message completely.
  AnyTone has also problems with the reception of SMS while the hang time after sending an SMS is still active. For this and for short SMSses, it is possible to activate a "Special Configuration" (see point 10)

0. ECHO - Function test

The ECHO command can be used to test whether the SMS send / receive works correctly.
When a text message comes back, everything is OK.
If no SMS is coming back, there is no need to test the other functions (except for the "Special Configuration") , since these will most likely not work :-(

The answer may look like this:

Hi Jens,
SMS which received by the system.

When you do not receive any answer and you did set the correct Brand for your transceiver in your BrandMeister SelfCare, please follow the instructions described in section 10 "Special Configuration".

1. Write SMS

To send an SMS to someone, start with the callsign, followed by a space and then the desired message.

As some transceivers (eg AnyTone or RT3) have problems with longer text messages, you should make sure that the message is not too long.

Mostly, SMSses containing more than 256 characters will be truncated to 256 characters. Furthermore, you can optionally enable the reduction to 127 characters (more information at section 10 at the end of this manual).

The receiver will be notified, next to your call, of the sending time of the SMS. These characters have to be deducted from the actual message !

When the recipient retrieves the SMS on the same day it was sent to him/her, the date will be suppressed.

DO1JG (23:06)
This is a test

If the SMS is retrieved the next day or later, the SMS also contains the date (and thus making it longer).

Retrieved the same year :

DO1JG (30.08 -. 17:50)
This is a test

Retrieved another year :

DO1JG (08/30/2018 - 17:50)
This is a test

This means that the header in can be 24 or 28 characters (line break are 2 characters), and in the case of a 6-digit callsign: 25 or 29 characters.

For example, since the AnyTone can receive only 127 characters, you should limit the actual message to 98 characters.

After having sent your SMS, you get a confirmation from the system that the message has been stored in the system.

Your SMS to DO1JG has been stored in the system

When you do not want the confirmation, you can disable it:
 

2. Receive SMS

There are several possibilities:

• automatic delivery
• notification that an SMS has been received
• manual retrieval

2.0 Requirements

For the notification and for automatic delivery, the radio ARS (Motorola) or RRS (Hytera) must have been enabled or the GPS position has to be sent regularly.
When the transceiver communicates with the BrandMeister system (via ID xxx999 (eg 262999)), it is checked if there are new SMSses available.

When using the automatic delivery, however, there is also the possibility that SMSses are lost. This can be when the time slot is blocked by other traffic short after communicating with the SMSC or when the reception is interrupted or bad.
When further automatic delivery or notification does not take place, the SMSses, however, are not lost and can still be accessed manually.

2.1 SMS Notification

By default, the "SMS Notification" option is enabled. This will send, by SMS, the number of messages in the INBOX (Conditions see 2.0)

You have 5 new SMS in your INBOX.
Send INBOX to 262995 to get a list or send GET to receive all SMS.

The number of new SMSses in this notification relates to SMSses for which you do not yet have been informed. When another SMS arrives at this point, the next notification would only give notice about 1 SMS.
The advantage of this system is that one can make free space for SMSses in the radio first, before retrieving them. Also, there will be no sudden reception of many unexpected messages.

2.2 Automatic Delivery:

The automatic notification is disabled by default, but can be enabled/disabled using the following command:

Once this feature is enabled, you get (under the conditions of 2.0) the SMS sent immediately to your device. The message is not deleted by the system after delivery and can thus later once again be retrieved.
The advantage of this system is obvious: you do not have to send commands to retrieve the SMSses. The downside is that you can get an unexpected number of SMSses at once and at least the AnyTone has issues with this (not receiving all SMSses or reboots).

Everyone must decide which system suits him or her the best. When you use Hytera or Motorola devices and you are not expecting a lot of SMSses, it makes sense to activate automatic delivery.
Nevertheless, one should query its INBOX regularly (see below) because SMSses can be lost sometimes.

2.3 Manual retrieval

No matter which option you have chosen, you can always retrieve the SMSses manually.

With the command INBOX (or short IN) you get a list of SMSses, stored in your inbox.
It is a numbered list, with the most recent SMS first.

A possible answer may look like this:

You have 9 SMS in your INBOX
1. DO1JG (23:06)
2. DO1JG (22:27)
3. DO1JG (22:21)
4. DO1JG (08/30/2018 - 17:50 )
5. DO1JG (08/30/2018 - 17:46)
6. DO1JG (08/30/2018 - 13:59)
7. DO1JG (08/30/2018 - 05:12)
8. DO1JG (08/30/2018 - 03:42)
9 . DO1JG (08/30/2018 - 03:41)

This answer would be 268 characters long and would not be displayed correctly on 'problematic' devices. Even Motorola and Hytera devices would not show the complete message.
For this reason, SMSses which are longer than 256 characters are generally shortened to 256 characters. Optionally you can, as already mentioned above, activate the reduction to 127 characters.
It is advised to regularly erase your SMSses from the INBOX (see below).

2.3.1 Retrieveof all SMSses in one go

With the command ALL (or alternatively GET) you instruct the system to send all SMSses to your device.
Note that, as mentioned above, not all devices may possibly handle a high number of SMSses at once.
The messages are not deleted from the system by this command and can be queried again if, for example, some text messages were not received.

2.3.2 query a specific SMS

With the GET command (or alternatively READ) one can retrieve a specific SMS.
<NUMBER> is the number of the SMS as shown with the INBOX command.
It should be noted that the number is not fixed to the SMS, but always the actual index in the INBOX. So if you delete a message in the middle of the list, the following SMSses will shift to the top and thus will be renumbered.

This feature is interesting for devices which can not process all SMSses at once.
In this case, with GET 1 one can always retrieve the most recent SMS.

3. Delete SMS

There are two possibilities: delete all SMS in the INBOX at once or delete a specific SMS.

3.1 Delete all SMSses

With the command DELETE (or alternatively DEL) you can delete all SMSses in the INBOX at once.
It makes sense once you have accessed the SMSses, to use this command to keep the INBOX clean.

answer:

All SMS to you has been deleted.

3.2. Delete a specific SMS

With the DELETE <NUMBER> command (or alternatively DEL <NUMBER>) you can delete specific SMS.
<NUMBER> is the number of the SMS as shown with the INBOX command.
It should be noted that the number is not fixed to the SMS, but always the actual index in the INBOX. So if you delete a message in the middle of the list, the following SMSses will shift to the top and thus will be renumbered.

Answer:

SMS has been deleted.

10. "Special configuration"

Note:
The "Special Configuration" is also valid for the service number 262993.
so the "Special Configuration" commands can also be sent to 262993.

10.1 query the current configuration

If one sends the command CONFIG, the current "Special Configuration" will be sent to the device by SMS.
When you do not get a SMS as a response, it is an indication you have to activate the "Special Configuration".

10.2 Enable or disable "Special Configuration"

You can enable or disable the "Special Configuration" as needed, depending on the device used.
Note : The settings will only be considered if the configuration is enabled.

10.3 SMS length for reception

AnyTone or RT3 users are strongly advised to activate the SHORT option, and of course also the "Special Configuration".

10.4 transmitting / receiving delay

The transmission / reception delay (an integer number, minimum 1 second and maximum of 10 seconds) is the time that elapses before the system will answer upon receiving an SMS command.
The default is 2.5 seconds.

The Anytone has an bug where no SMSses will be received during the hang time after sending an SMS.
Values of 7...10 have been proved to solve this.

10.5 Reset Configuration

The CONFIG RESET command will reset the "Special Configuration" back to the system default.
In the meantime, the "Special Configuration" is also disabled.