Send text message (SMS)
SMS optimizer
To reduce the average SMS length, a parser (transliterator) has been developed that will replace special ‘Latin’ characters with their regular counterparts. Some examples of the mappings that are applied:
ê, ę → e
ç → c
ó, ő, ô → o
ř → r
…
Applying this transliteration will have the effect that fewer messages will need to be encoded in a special way (which limits the number of characters per message to 70). The impact on readability is expected to be limited.
The parser will be enabled with a hidden configuration setting. Customers will be asked to opt-in if they want to activate the parser.
The transliteration algorithm will not change anything to Cyrillic messages.
An example
Before transliteration: 9 text messages are required for sending out this single communication.

After transliteration: only 4 messages are required

SMS message fail to deliver notifications
Acceptable failure rates
We have learned that it is impossible to guarantee the delivery of a text message. After substantial research on the delivery rate of text messages, we must conclude that a failure rate of 1-2% is normal behaviour.
As some text messages are business critical (e.g. calling of a driver after a dispatch), we foresee a way to get notified when a text message is not arriving within 10 minutes.
Notifications on non-delivery
A notification will be sent when a text message fails to deliver or we don’t get a response within 10 minutes. The notification will appear in the top right of the screen and will contain the content of the text message, translated in one of the languages of the management portal.

The notification can be acknowledged once the necessary action was taken to inform the driver. This way you can make it clear for everyone that no further actions are required.
Won’t do / limitations
We cannot cover for drivers registering with wrong phone numbers, that still exist. Then someone else will gets a message.
We cannot cover for drivers ignoring text messages.
More information
Different status of text messages that do not arrive
After sending a text message to Twilio we listen for the result. There are several possible states of the message in Twilio. Each status in Twilio is mapped to a Peripass status:
Twilio status | Peripass notification |
---|---|
Outbound Message Status Progression This tracks the status when the message is being processed by Twilio: | |
accepted, scheduled, queued, sending, sent | only after 10 minutes in this state: NO RESPONSE NOTIFICATION |
Finalised message delivery status This tracks the status after the message is being send to the mobile carrier. | |
sent, delivery_unknown | only after 10 minutes in this state: NO RESPONSE NOTIFICATION |
failed, undelivered | MESSAGE FAILED NOTIFICATION |
delivered | No notification as everything happened as expected. |
no response from Twilio | When we don’t get an update from Twilio at all after 10 minutes, we trigger a NO RESPONSE NOTIFICATION |
MESSAGE FAILED NOTIFICATION example:
Text message not delivered to +3212345678
NO RESPONSE NOTIFICATION
Peripass could not verify if a text message was delivered. Please check with the visitor: +3212345678
Can I limit the notifications per site?
Notifications are only shown for visitor a user has permissions to see. As a result, a user for a specific site will only see notifications for the visitors of that specific site.
Troubleshooting
When to contact support in case a text message is not arriving?
An arrival success ratio of 97% is considered normal behaviour. In case you have doubts on whether the amount of text messages exceeds this number, then you can use the following rule of thumb:
There are less then 5 different phone number in the last 24 hours (this equals to roughly 5% for an average of 100 trucks per day)
There are less then 15 different phone numbers in the last 5 working days (this equals to roughly 3% for an average of 100 trucks per day)
This is considered normal behaviour.
If you see more then this, then please contact support for a more in depth investigation.
Message not delivered because country is not enabled for SMS Delivery
We need to configure which countries our service can send text messages to. By default, not all countries are enabled; some are flagged by Twilio as high-risk for text message fraud, and activation for these countries is not recommended.
Due to this configuration, there may be instances where text messages are not delivered. We monitor blocked messages on a monthly basis and evaluate if adjustments to the country settings are necessary.
As of this writing, the currently disabled countries for SMS delivery are:
Asia
Azerbaijan
Bangladesh
Indonesia
Israel
Oman
Pakistan
Palestina
Sri Lanka
Tajikistan
Vietnam
Africa
Algeria
Nigeria
Tunesia
Enabled countries:

An update of the disabled countries can be asked to support.
Message not delivered because Alphanumeric Sender ID not registered
An Alphanumeric Sender ID is your company name used as the Sender ID in one-way SMS messages sent to supported countries. This way, drivers don’t get a text message from any random American Phone number, but see instead “Peripass” or “Your customer name” as sender.
Not all countries support Alphanumeric Sender IDs, and many that do require you to register your Alphanumeric Sender ID before it is first used. This can be a reason why text messages are not delivered to specific drivers.
Here is a list of countries that support Alphanumeric Sender IDs which includes the pre-registration requirements for each one.
If your customer has a significant number of drivers in countries requiring Sender ID registration, our Support team can assist you in registering these Alphanumeric Sender IDs.
More information, seehttps://behindthebuttons.atlassian.net/wiki/spaces/DAM/pages/111476824/Twilio+account+configuration#Configuring-the-Messaging-Service
Your delivery data is incorrect, we believe the nondelivery is much higher.
As the delivery rate is crucial for our customers, we have done substantial research to support our conclusion about the average nondelivery. We have done the following:
We have analysed delivery statistics from our text message service, covering more then 500.000 text messages send by Peripass.
As some customers stated our data was incorrect, we wondered whether the statistics we received from our partner Twilio were incorrect. Therefore we compared the statistics with the experiences on-site in the following 2 experiments:
On-site UX research for 5 full days with 5 different customers.
Monitored of 6 pilot customer for more then 4 months.
Based on this research we learned that the observations on the field correspond with the percentages we observe. However, we noticed other dynamics creating a nondelivery perception of text messages:
Drivers that provide a phone number of someone else.
Drivers that ignore the text message.
Conclusion: Our product & engineering team has not seen any indication that our statistics are not trustworthy. Therefore we decided to only perform deeper investigations for customers for which the statistics are higher then the average 3% nondelivery rate.