Science Power

Hotel Phone System (VoIP) Hotel Phone System should be a must for most hoteels or motels, which has been using Analog Phone System(Analog PBX) in past decades.  There were some technical and financial issues if swifting to IP-PBX: 911 service IP-phone expensive than analog hotel phone Ethernet cable running Billing System Solution for replacement: e-911 are supported  VoIP gateway Sharing same Ethernet cable with IPTV A2billing Module for IP-PBX Therefore, you could  build a PBX  for hotels or motels if you are the owner  Analog VoIP Gateway For Hotel Phone System IP phone is recommended because many functions can work only on IP phone, but IP phone still expensive than analog hotel phone. Alternatively, hotels or motels can use VOIP gateway instead. In addtion, no need to run Ethernet cable. Software for For Hotel Phone System Issabel FreePBX FusionPBX You should consider Issabel or FreePBX first:Issabel with very friendly Web console and almost all modules are...

Get a free PBX? Get a free PBX? Absolutely possible if you have some unused old PC, chromebook or ARM-device, but you need basic knowledge on computer and Linux. Free hardware: For a beginner, the cost on hardware might not be a problem because you could build a PBX on virtual machine like VMware or virtualbox. However VMware is not free product, so you can start with free virtualbox. Alternatively, you can use some old unused device or PC to have a try.  Asterisk and freepbx can works on below equipment. Old x86 PC with min. 512MB memory and at least 1GHz x86 CPU Chromebook or Chrombox: need to flash BIOS and boot from external USB drive ARM devices:  below devices were tested. Dockstar Pogolug GoFlex Home and Net Raspberry Pi:  Zero, 2, 3 and 4 Orange Pi: One, PC and PC2 Free software for a Free PBX: FreePBX AsteriskNOW Issabel FusionPBX (Freeswitch) PBXinAFlash OpenSIPs Kamailio OpenPBX 3CX (kind of free) As a beginning, FreePBX is recommended because it has friendly w...

SIP Softphone on Smart Phone SIP softphone on smart phone can be used as PBX’s extension in either WIFI or cellular network. Moreover, you can add a DID number to your SIP account. If so, SIP softphone could be the alternative of cellphone. Free SIP Softphones on smart phone: You may use free SIP softphone as PBX’s extension instead of IP phone or VOIP gateway for Analog phones. This might be important to get  a Free PBX Grandstream wave lite Free Free G729, G722 and Opus codec Multi-account Support SIP message Support both Android or iPhone No Push Nortification Zoiper: Free version with only one SIP account Paid G729, G722 and Opus codec Support SIP message Paid Push Noritication Suport both Android and iPhone Linphone : Free Multi-acccount Free G729, G722 and Opus codec Support SIP message Support Android only Push Notification not working Paid SIP Softphone on Smart phone Groundwire One-time pay Multi-acccount G729, G722, Opus codec included Support SIP message Support both And...

CentOS Firewall:  firewalld commands I. Introduction Centos7 and above releases have tried to bring firewalld firewall, firewalld to bring iptables firewall.  The reason is that the firewall policy of iptables is handled by the netfilter network filter at the kernel level, while firewalld is handled by the nftables packet filtering framework at the kernel level.  Compared with iptables firewall, firewalld supports dynamic update technology and adds the concept of zone.  To put it simply, the area is that firewalld has prepared several sets of firewall policy sets (policy templates) in advance. Users can choose the appropriate policy set according to different production scenarios to achieve rapid switching between firewall policies. Zone is a major feature for firewalld, but for us, Centos7 is generally on the server, and there is less need to switch zones, so this article will not introduce it. There are more online information. You can go to Baidu to find informati...