Understanding SIP and RTP in Asterisk In a standard VoIP setup, SIP is used for signaling—establishing, managing, and terminating the call. Once the call is established, RTP (Real-Time Transport Protocol) carries the actual voice media. By default, Asterisk can either relay the media (RTP flows through Asterisk) or allow direct media, where RTP flows peer-to-peer … Read more
Description Caller ID Number (CID) is a telecommunications feature that provides the recipient of an outbound call with the phone number of the caller. When you make a call, this service transmits your phone number, allowing the callees to see who is calling before they answer. This feature enhances communication by enabling callee to screen … Read more
Description The Network Status indicating “NAT Type: UDP Blocked” means that the Grandstream IP Phone has detected that the SIP port is not properly port forwarded. Suggestions Note: STUN may not work with all routers, particularly those with Symmetric NAT enabled. References SIP ALG and why it should be disabled on most routers What is … Read more
Description This article explains the differences between Account Mode and Line Mode in the Grandstream High-end Color GXP21XX IP Phones, particularly regarding the Virtual Multi-Purpose Keys (VMPK) settings. When the phone is in Line Mode Dynamic Key Switching: If a line button is assigned only to Account 1, pressing the Account 2 key will dynamically … Read more
Description Setting up a NAS server with Grandstream IP PBX UCM63XX provides a powerful and versatile solution for business needs. It centralizes and stores the data, and provides redundancy and reliable systems. How it works
The priorities of ringtones are played as follows, from high to low in the Grandstream IP Phone GRP260X series：1. Distinctive Ringtone (Type B)2. Contact Ringtone (under Contacts > Local or Remote Phonebook)3. Group Ringtone4. Distinctive Ring Tone (Type A)5. Account Ringtone6. System Ringtone
Description This article describes the behavior of whether the Grandstream GWN76XX meshed access points (Range Extender RE) are set in DHCP mode or Static IPs. When the REs are configured with Static IPs, they may go offline and cannot be discovered even if the LEDs are solid blue. It is recommended to configure the REs … Read more
Description This article describes the behavior of Grandstream GWN700x series routers always showing zero Upload or Download Speed for the Client devices. When the Hardware Acceleration is enabled under Network Settings > Network Acceleration, the offload packets from the CPU are not counted The packet will be offloaded only if: a. It is the first … Read more
Description This article briefly describes the Security Settings parameter in Grandstream IP Phones GRP261x series. It is important for debugging when the phones are registered via TLS/SSL. ‘Validate Server Certificates‘ is mainly used for Web Interface or SSH access. ‘Check Domain Certificates‘ is to check a domain using the Trusted Domain Name List. ‘SSLKeyLogFile‘ is … Read more
Description This article describes the best practices to free up the data partition in Grandstream IP PBX UCM to avoid abnormal behaviors such as call drops, delays, and slow performance. The UCM62XX or UCM6510 series has a config partition of only 200MB while the UCM630X series has a 500MB config partition. The data partition is … Read more