| E1 | T1 | |
|---|---|---|
| Regions | India, Europe, Australia | US, Canada, Japan |
| Line rate | 2.048 Mbit/s | 1.544 Mbit/s |
| Channels | 32 timeslots: 30 voice (B), 1 signalling (D), 1 framing | 24: 23 voice (B) + 1 signalling (D) on PRI |
| Calls per line | 30 | 23 |
| Channel speed | 64 kbit/s | 64 kbit/s |
Connecting PRI to VoIP
- PRI card – fits inside the server (Sangoma A101–A116, OpenVox D130–D1630E).
- PRI gateway – separate box that converts PRI to SIP (Dinstar MTG, Sangoma Vega).
- Echo cancellation is recommended for clear voice when calls pass between PRI and VoIP.
Related: IP-PBX · IVR System · Call center dialer
Frequently asked questions
Does India use E1 or T1?
India uses E1. A standard E1 PRI line carries 30 simultaneous voice calls.
How many calls can one PRI line carry?
An E1 PRI carries 30 calls; a T1 PRI carries 23 (or 24 without a dedicated signalling channel).
How do I connect a PRI line to a VoIP system?
Use a PRI card inside the server running the PBX, or a separate PRI (E1/T1) gateway that converts to SIP.