AT Command Set

•Take into account that a delay of 100 ms is required between a response to the last command (e.g. OK) and the next command on the same line.

•When you enter AT+IPR=0, autobauding will be activated after the response to the last command is received.

•When local echo is active (ATE1) and you enter AT+IPR=x with other com- mands you may encounter the following problem: If switching to the new bit rate takes effect while a response is being transmitted, the last bytes may be sent at the new bit rate and thus, not properly transmitted. The following com- mands will be correctly sent at the new bit rate.

2.45.1Autobauding

Autobauding allows the GSM engine to automatically detect the bitrate configured in the host applica- tion. The serial interface of the GSM engine supports autobauding for the following bitrates: 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200. Factory setting is autobauding enabled. This gives you the flexibility to put the GSM engine into operation no matter what bitrate your host application is configured to.

To take advantage of autobaud mode specific attention must be paid to the following requirements:

Synchronization between DTE and DCE

Ensure that DTE and DCE are correctly synchronized and the bitrate used by the DTE is detected by the DCE (= ME). To allow the bitrate to be synchronized simply issue an "AT" or "at" string. This is necessary

•after you have activated autobauding

•when you start up the GSM engine while autobauding is enabled. It is recommended to wait 3 to 5 seconds before sending the first AT character. Otherwise undefined characters might be returned.

If you want to use autobauding and autoanswer at the same time, you can easily enable the synchro- nization, when you activate autobauding first and then configure the autoanswer mode (ATS0=0).

Restrictions on autobauding operation

•The serial interface has to be operated at 8 data bits, no parity and 1 stop bit (factory setting).

•The A/ command (and a/) cannot be used.

•Only the strings “AT“ or “at“ can be detected (neither “aT“ nor “At“).

•The Unsolicited Result Codes "^SYSSTART", "^SYSSTART ALARM MODE" and "^SYSSTART CHARGE-ONLY MODE" are not indicated when you start up the ME while autobauding is enabled. This is due to the fact that the new bitrate is not detected unless DTE and DCE are correctly syn- chronized as described above.

•Any other Unsolicited Result Codes that may be issued before the ME detects the new bitrate (by receiving the first AT command string) will be sent at the previous bitrate.

•It is not recommended to switch to autobauding from a bitrate that cannot be detected by the auto- baud mechnism (e.g. 300 baud). Responses to +IPR=0 and any commands on the same line might be corrupted.

•When entering several AT commands on the same line, consider the requirements described in the Notes of Chapter 2.45.

•See also AT+ILRR Set TE-TA local rate reporting , pg. 37

Autobauding and multiplex mode

If autobauding is active you cannot switch to multiplex mode (see +CMUX, pg. 91). Vice versa, when you run the multiplex mode, the write command AT+IPR=<rate> cannot be used.

MC35_ATC_01_V04.00

Page 40 of 238

02.04.2002

Page 39 Page 41
Page 40
Image 40
Siemens MC35 manual Autobauding, Synchronization between DTE and DCE, Restrictions on autobauding operation
Page 39 Page 41

MC35 specifications

The Siemens MC35 is a compact and versatile modem designed primarily for mobile communication, data transmission, and machine-to-machine (M2M) applications. Launched in the early 2000s, it quickly became popular due to its blend of performance, reliability, and ease of integration, making it a solid choice for developers and businesses.

One of the key features of the MC35 is its support for GSM and GPRS technologies. This allows it to connect seamlessly to various networks, enabling users to transmit data at speeds that were impressive for its time. The GPRS capability can offer data rates of up to 171.2 kbps, allowing for efficient data transfer even in areas with limited connectivity.

The MC35 is designed to support both SMS and voice functionalities, making it adaptable for a range of applications. This includes remote monitoring, telemetry, and alarm signaling. The ability to send and receive SMS messages is a significant advantage for applications that require immediate alerts and notifications, enhancing its utility in security systems and industrial automation.

Furthermore, the modem is equipped with a range of interfaces, including serial communication (RS232), which makes it compatible with various hardware devices. This facilitates easy integration into existing systems, whether for industrial machinery or consumer electronics. Additionally, it features a robust software development kit (SDK), which enables developers to create custom applications tailored to their specific requirements.

Power consumption is another notable characteristic of the Siemens MC35. It is engineered to be energy-efficient, which is especially important for battery-operated devices or systems that require a prolonged operation without frequent recharging or maintenance.

In terms of physical characteristics, the MC35 is compact and lightweight, allowing it to fit into various enclosure designs without occupying much space. Its durability ensures it can perform reliably in different environments, making it suitable for outdoor and industrial applications.

To summarize, the Siemens MC35 stands out as a reliable modem with a rich feature set that includes GSM and GPRS support, SMS and voice capabilities, easy integration through various interface options, and energy-efficient operation. Its adaptability makes it a valuable tool for a wide array of communication and data transmission tasks, solidifying its place in the evolution of mobile communications technology.
Top Page Image Contents