You may use any string of characters for a phone number entry but it is recommended that you follow some rules. This is especially necessary if you plan to synchronize your contact data with mobile devices or to use automatic dialing e.g. with the Skype Toolbar.
Please note the following hints:
- Always use the same format for all phone, fax and mobile numbers. Do not enter any text in the CRM fields.
- In Germany there is a standard for the phone number format called DIN 5008. This of course is not valid for other countries but the rules are simple and seem to work in other countries also. Do not use any brackets or lashes. Instead sepearate prefix and phone numers by a space character. You may use the – character for separating sub numbers.
- For international numbers we recommend to use OO in front. It is common that the + sign is used but as some of our customers reported that this may create problems if you synchronize contacts for mobile devices e.g. by using the Outlook Plugin. Dependig on the device type and manaufactuer sometimes the + character disappears which makes it impossible to dial automatically.