Inbound vs Outbound DIDs
Understanding the distinction between inbound and outbound numbers is essential for correctly configuring your telephony infrastructure.
Inbound DID numbers
An inbound DID (Direct Inward Dialing) is a phone number that your customers and partners call to reach you.
- Flow: Public telephone network → WebTic network → Your PBX/SIP Extension
- Examples: Your customer support number, main switchboard, fax
- Format: Geographic numbers (01-05, depending on the département), non-geographic numbers (09), toll-free numbers (08)
- Billing: Fixed monthly subscription per number — inbound calls are generally included (check depending on the plan)
Outbound numbers (CLI/Caller ID)
The outbound number (CLI — Calling Line Identity) is the number displayed to the person you call when you call them.
- Flow: Your PBX/SIP Extension → WebTic network → Public telephone network → Recipient
- Configuration: Via the SIP header
FromorP-Asserted-Identity - Restriction: You can only display numbers that belong to you (fraud prevention)
- Billing: Per minute (depending on the destination called)
Comparison table
| Criterion | Inbound DID | Outbound (CLI) |
|---|---|---|
| Who calls? | Your customers → You | You → Your customers |
| Billing | Fixed subscription | Per minute used |
| Quantity | 1 number = 1 DID | Can vary depending on configuration |
| Configuration | Routing in client area | SIP From/PAI headers |
| Simultaneous capacity | Depends on the trunk | Depends on trunk channels |
Bidirectional DID
It is possible to use the same number for both inbound and outbound. The configuration is:
- Order a WebTic inbound DID
- Configure this number as the CLI on your outbound trunk
- Your contacts see your DID number → they can call back on this same number
Number presentation
# Asterisk configuration (sip.conf or pjsip.conf) fromuser = YOUR_DID_IN_E164_FORMAT # Example: fromuser = 33142424242
# 3CX configuration Admin → Outbound Rules → Presentation number: select the DID
