VoIP comes with a lot of abbreviations. Here are the ones you are most likely to meet when setting up a dialer, with short definitions and links to guides that go deeper. Definitions are general, and your provider may use a slightly different name for some items.
Account and setup terms
| Term | Meaning |
|---|---|
| SIP | Session Initiation Protocol. The signalling method used to start, manage and end calls. See what a mobile SIP dialer is. |
| Registration | The dialer signing in to the server so it can make and receive calls. See registration troubleshooting. |
| Username / SIP ID | The identifier of your account on the server. |
| Password | The secret used to prove the account is yours. Keep it private. |
| Server / domain / host | The address of the provider's SIP server. |
| Port | A numbered network entry point on the server. Leave the default unless told otherwise. |
| Transport | How SIP messages travel: UDP, TCP or TLS. |
| Operator code / brand prefix | A provider-specific code some dialers use to identify which service to connect to. |
| Brand PIN | Another name used in some dialers for the provider-issued code that links the app to a provider. See the MoSIP Brand PIN page. |
Network and provider terms
| Term | Meaning |
|---|---|
| Softswitch | Software that routes calls between networks and manages accounts and billing for a VoIP provider. |
| Gateway | A system that connects VoIP calls to a traditional phone network. |
| PSTN | The public switched telephone network: ordinary landline and mobile networks. |
| Route | The path a call takes towards its destination. Quality and features can differ by route. |
| Termination | Delivering a call to its final destination network. |
| DID | Direct inward dialling: a phone number that can receive calls, which a provider can point to your account. |
| CLI / caller ID | The number shown to the person receiving the call. See why caller ID may not show. |
| White label | A service or app sold under another company's brand name. |
Audio and quality terms
| Term | Meaning |
|---|---|
| Codec | The method used to encode voice into data and decode it again. See codecs explained. |
| Bandwidth | The amount of data per second your connection can carry. |
| Latency | The delay before audio reaches the other person. |
| Jitter | Variation in packet arrival time, which can make audio choppy. |
| Packet loss | Voice packets that never arrive, causing gaps in audio. See call quality. |
| NAT | Network address translation. A router feature that can sometimes interfere with VoIP audio. |
| One-way audio | A call where sound flows in only one direction. See one-way audio fixes. |
Dialer terms
A softphone is any app that acts as a phone. A mobile dialer is usually a softphone set up for a particular provider. MoSIP is published by Voxvalley Technologies and iTel is a dialer product line from Reve Systems. Your calling minutes come from your account with a provider, not from the app itself.
More terms you may come across
| Term | Meaning |
|---|---|
| RTP | Real-time Transport Protocol. Carries the actual voice packets during a call. |
| STUN / TURN / ICE | Techniques that help calls pass through routers and firewalls so both sides can hear each other. |
| SIP ALG | A router feature that rewrites SIP traffic. It can help or cause problems, depending on the router. |
| DTMF | The tones sent when you press keys during a call, used for phone menus. |
| Trunk | A bundle of call capacity between a company and a provider. |
| IVR | Interactive voice response: an automated phone menu. |
| CDR | Call detail record: a log entry for a call with time, number and duration. |
| ASR | Answer seizure ratio: the share of attempted calls that were answered. |
| ACD | Average call duration, or in call centres, automatic call distribution. |
| MOS | Mean opinion score: a 1 to 5 rating of call quality. |
| Failover | A backup route or server that takes over if the main one fails. |
| Reseller | A business that buys calling capacity or accounts from a provider and sells them on. |
How the terms fit together
Think of a call as a journey. Your dialer registers with your provider's softswitch using your username, password and, if needed, a Brand PIN. When you dial, the softswitch picks a route, often through a gateway to the traditional phone network. The two sides agree on a codec, and RTP packets carry your voice along the path. Latency, jitter and packet loss describe how well those packets travel. If something goes wrong, SIP response codes and call logs help show where.
Knowing even a handful of these terms makes support conversations easier. For example, saying "the app registers but there is one-way audio on Wi-Fi" immediately tells the team that sign-in works and that the problem is in the voice path, so they can skip the credential checks.
Terms that sound similar but are not the same
- Registration versus a call. Registering is signing in. A call is a separate action that can still fail.
- Balance versus validity. Balance is how many minutes remain. Validity is how long they can be used.
- Caller ID versus your account number. Caller ID is what the other person sees. Your account username is only for signing in.
- Reseller versus developer. The developer builds the app. The reseller or provider supplies your calling account.
If you meet a term that is not listed here, ask us on WhatsApp and we will explain it in plain language.
Next step: Still unsure about a term in your setup message? Ask us on WhatsApp and we will explain it.
Frequently asked questions
Is Brand PIN the same as password?
No. A Brand PIN identifies the provider or service in the app, while the password protects your individual account.
Is an operator code the same as a Brand PIN?
They serve a similar purpose in some setups, but names differ between providers and apps. Use exactly what your provider issued.
Do I need to understand all these terms to make calls?
No. Most people only need username, password, server and, where required, a code. The rest is helpful for troubleshooting.
