IP Phone related

Do we need manageable switches?
How QoS Impacts Your VoIP Calls

pbxes.com:
..Setup \ Extensions \ SIP:
....Ext. number: 100
....Password:
..On android softphone:
....Host: 188.40.65.148 (obtained from Wiki \ Getting Started)
....Username and Password: as you've entered when creating extension

Overview of an IP PBX System (IP Phone System)
www.voiplink.com/IP_PBX_Overview_s/326.htm

trixbox CE Frequently Asked Questions
http://fonality.com/trixbox/wiki/trixbox-ce-faq
- How do I connect analog lines to a trixbox?
- Can I send/receive faxes with trixbox?

SIP Wi-Fi Phone with Peer-to-Peer support:
Planet VIP-192
www.simantap.com/planet/55-planet-vip-192-sip-wi-fi-phone.html
Linksys Wireless-G IP Phone WIP-330
www.klikbelanja.com/voip/voip-wireless/ls-wip330.html
Locktec WP04 IP SIP Phone
http://sipphonereport.com/sip-phone-review-3-locktec-wp04-ip-sip-phone.aspx
www.yippz.com/wp04-wifi-phone.html

VoIP Gateway: positioned as FXO or FXS?
FXS port was connected to your telephone sets or Trunk Line of PBX.
FXO port was connected to the extension port of a PBX or directly connected to a PSTN line of carrier.

What do the terms FXS & FXO mean
www.nicherons.com/faq-fxo.html

a reference guide to all things VOIP
www.voip-info.org/

Local IPPBX
www.briker.org/features

How Analog Telephony Adapters (ATA) Connect IP PBX to FXO (Analog Trunks) and FXS (Analog Stations
www.excitingip.net/291/ata-analog-telephony-adapter/
...The fax machine in the Head Office also connects to the IP Telephony Server (VOIP Server) through the FXS Gateway H and hence can send and receive faxes through the PSTN network.
...its better to check if the ITSP (Internet Telephony Service Provider) can provide service all the regions that you want to dial out (to any cell phones/ land-lines in those regions). In some countries (Like India), ITSP cannot yet provide Local and STD call service over the Internet due to regulation.
...the analog phones (from one location) can access the analog trunks (in another location) through the gateways and dial out to any phone number using the analog trunks. So, someone sitting in one location makes a call to any phone number in another location and still pays only local call charges! Again, this is not allowed within certain countries (like India)
...A traditional Analog/Digital EPABX can be connected (integrated) with an IP PBX with limited number of channels (of communication between them) using the Analog Telephony Adapters.

Q:Billing? Yes
Google: elastix|trixbox|asterisk billing

Q:Handset price?
www.imaxnet.com/products/en/index.php

Q:ITSP in Indonesia?
www.infoasiatelecom.com/rates.php