FAQ
What does the term online mean ?
In the GPRSPortal the termini online and offline are used in two different contexts:
- Modem offline, this means the Modem/Terminal is not connected to one of the Servers of the KMCluster, this can be due to one of the following reasons:
- No server is reachable (IP misconfiguration of the VPN or gateway, or a problem at the computer centre)
- a hardware defect of the modem or (more likely) the power supply
- a broken installation/configuration (can only happen after an errorness installation or due to a failed update)
- SIM card failure
- no or very low antenna signal (e.g. MFP was moved to another place)
- Modem/Terminal was disconnected from power
- MPF offline, this means the MFP is not answering to data requests, this can be part of normal operation or indicate a problem. Theses are the possible reasons:
- MFP is powered down or in a sleeping mode (depends on the MFP type, most office printing machines stay online, while production printing machines go offline), this is due to normal operation and is no problem at all
- the serial cable is disconnected from modem or MFP
- the MFP does not recognize the connected Modem/Terminal and shows an error message in its Display, when this happens the serial interface of the MFP has a problem, on some types it can be reactived by a reboot of the Modem/Terminal (the 3xx versions of the Midlet attempt this automatically) or even worse, the MFP has to be power cycled
What happens if my MFP displays a message like: please connect Modem
In this case the serial interface of the MFP has a problem. The new Midletversions (3xx) should deal with this problem for most MFP types. But for some MFPs this problem can only be fixed by powering down the MFP.
How much traffic does a Modem produce
This question is answered by the following article: Modem Traffic Calculation
What does the blinking LED mean ?
This question is answered by the following article: LED Pattern EGS5
Why are some registrations/setups failing ?
There are some reasons why a registration/setup of a MFP is failing:
- The machine_id is not registered at the correct center in CSRC, be careful it takes some time from adding a new MFP (e.g. in the Webapplication) until this information is spread to all subunits
- Communication with the Server fails
- It takes too long for the Modem to check with the Server if the MFP is known
- The Modem expects the MFP on the wrong serial speed, it will change its speed settings but that attempt is lost
As a general rule, try at least three attempts before giving up. You can check with the GPRS Portal if the MFP is known at the Server.
Howto register another MFP with an already registered Modem ?
MFPs are working with two different serial speeds, 9600 and 38400 baud. At the first registration/setup the application determines this speed (recognicing of expected messages) and locks the Modem to this baudrate. If you want to connect a registered Modem to another MFP, the MFP has to use the same bitrate as the one formerly connected with the Modem. If this is the case, just perform a setup. If the speeds differ, you have to use the GPRS Portal and reset the Modem, this will release the lock on the Modem. An unlocked Modem will attempt to determine the correct serial speed and the setup should succeed.
Howto test SIM (public access) cards of a new Carrier/Provider
If you want to test a SIM card of a new carrier or provider, you have to check or validate the following tasks:
- Be sure that GPRS is enabled in the choosen tarif (there are e.g. UMTS only data sims)
- Be sure that all internet access is allowed in the choosen tarif (there are some SIMs which allow e.g. only http traffic)
- Find out the access data (APN, username, password)
- Find out the imsi prefix of the used SIMs, this are the first digits of the imsi number, which identifies the SIM card in the GSM net. In the most cases all cards of one carrier start with the same digits. This number is used in the autoconfiguration modus of the Modem.
- Maybe you can also find out the TCP idle timeout, thats the time a TCP Socket is allowed to stay open without any traffic flows. Most used numbers are 5, 10, 15 and 30 minutes
If you have collected all this information there are two ways to go on:
- Use the GPRSConfigurator to set the access data to a test modem, unlock the PIN of the SIM card, insert the SIM into the Modem and power it up. Check with the GPRS portal if the modem is going online, if yes than only the tcp idle timeout has to be evaluated. If all data is validated please inform us about this data, we can add the data to the internal list, used by the Modems for selecting correct access data.
- Send us all informations you have, and we add the data to the internal list, used by the Modems for selecting correct access data and generate a new Modem software version inkluding the new list. Update the Testmodem to the latest Software version, unlock the PIN of the SIM card, insert the SIM into the Modem and power it up. Check with the GPRS portal if the modem is going online.
Howto test SIM (private access) cards of a new Carrier/Provider
Private access means that the SIM cards need a private APN setting, this will usually result in another IP range than with public APNs and most times a VPN. You need to perform the same action like with public access SIM cards but have to ensure that the Modems can reach the cascade servers (look at StartingPoints to check for the actual IPs of these servers). This can be done by connecting the VPN to the computer center in Langenhagen, or to open the access from the private IP range to the cluster servers.
Howto estimate the costs of a SIM card
Most important are:
- the choosen tarif:
- rounding limits (blocksize, timing limits, gprs sessions)
- availability of data pooling (good working modems will generate less traffic than bad working modems)
- availability of sim card management platform (activation and deactivation of sims, debug information, quotas, notifications on errors, changing of tarif option, prolongation of tarifs ...)
- traffic estimation:
- how often do you want to perform data requests (daily, weekly, monthly), the size of a data request depends on the MFP type and ranges from less than 1k to around 50k, the modem uses a compression so that this sizes will be reduced by a factor 2 to 4. So for exact calculation the fractions of different MFP types in your fleet must be known.
- the traffic for just keeping the connection open is calculated here Modem Traffic Calculation
A rough estimation averaged over a fleet with daily (monday - friday) data request and a tcp-idle-timeout of 30 minutes, is 1 MByte per month. But this is only the real traffic, no roundings. If you have many production printers in your fleet than the value can be higher, if the tcp-idle-timeouts are shorter the traffic will be higher, and if you have many modems with poor antenna receiving values than the numbers will be higher as well.
Howto change a SIM card
A sim card can be replaced without problems, just to make sure to disconnect the Modem from power, before replacing the SIM card.
Howto replace a modem at a MFP
Perform a RAM CLEAR at the MPF and than a SETUP (registration), without this the modem wont be able to communicate with the MFP. If the modem was working with another MFP on a different baud rate setting, it needs to be resetted (via M2MPortal).