## 7 Conclusions  
This paper presents the Location Transparency Call (LTC) system, which bridges IoT with phone technologies to build an intelligent telephony solution for business enterprises. LTC is an application of the Phone of Things (PoT), and it inherits its architecture. LTC provides an intelligent phone dialing solution to mitigate missed business calls. LTC tracks the mobility of the users within the premises using RFID tags carried by the users and a set of RFID-enabled nodes installed at each door entry and connected wirelessly to the PoT gateway, which maps the users to the closest extension numbers at their current locations. The PoT gateway automatically and dynamically forwards all incoming calls indented to an employee to the nearest extension number. We demonstrated the proposed system architecture and highlighted the motivation behind utilizing the enabling technologies operated by the system. We conducted a feasibility study of the proposed system by evaluating the performance of tiny and cost-effective embedded Linux platforms when acting as Asterisk servers for LTC applications. The results of the feasibility study are impressive. The results promote the utilization of embedded Linux platforms as appro  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**No.** & **Name** & **RFID Tag No.** & **Reader ID (t \(-\) 1)** & **Reader ID (t)** & **Location** & **Extension No.** \\ \hline
1 & [PERSON] & 1 & 10 & 10 & Not Exist & 1000 (Fallback) \\
2 & [PERSON] & 2 & - & 10 & Reception & 1000 \\
3 & [PERSON] & 3 & 20 & 20 & Reception & 1000 \\
4 & [PERSON] & 4 & 10 & 20 & Room 1 & 1001 \\
5 & [PERSON] & 5 & 20 & 30 & Room 2 & 1002 \\
6 & [PERSON] & 6 & 10 & 40 & Room 3 & 1003 \\
7 & [PERSON] & 7 & 30 & 40 & Room 3 & 1003 \\
8 & [PERSON] & 4 & - & 20 & Invalid & 1000 (Fallback) \\ \hline \hline \end{tabular}
\end{table}
Table 4: Entering and exiting illustration example.  
priate candidates to act as PoT gateway in small-to-medium-sized business domains. The results show, for example, that Raspberry Pi 4 B can gracefully handle 182 simultaneous passthrough VoIP calls. However, Raspberry Pi Zero W, the least influential member of the Raspberry Pi family, can gracefully handle 12 simultaneous passthrough VoIP calls. For large-scale business applications, however, we discussed the utilization of the PoT gateway as an integral addition to the existing UC solution which will enrich it with LTC capabilities. We also discussed other possible applications of LTC to bring it expand it utility.  
Writing--original draft, H.K.; Writing--review & editing, K.E. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Natural Sciences and Engineering Research Council of Canada (NSERC) grant number CRC-2017-00170.  
Not Applicable, the study does not report any data.  
The authors declare no conflict of interest.  
The following abbreviations are used in this manuscript:  
\begin{tabular}{l l} AI & Artificial Intelligence \\ AGI & Application Gateway Interface \\ API & Application Programming Interface \\ ATA & Analog Telephone Adapter \\ CoSIP & Constrained Session Initiation Protocol \\ CPU & Central Processing Unit \\ DBaaS & Database as a Service \\ DIY & Do-It-Yourself \\ IoT & Internet of Things \\ IP & Internet Protocol \\ ITSP & Internet Telephony Service Provider \\ IVR & Interactive Voice Response \\ LAN & Local Area Network \\ MCU & Microcontroller Unit \\ MQTT & Message Queuing Telemetry Transport \\ NFC & Near Field Communication \\ PBX & Private Branch Exchange \\ PoT & Phone of Things \\ PSTN & Public Switched Telephone Network \\ RFID & Radio Frequency Identification \\ RTP & Real Time Protocol \\ SDN & Software-Defined Networking \\ SIP & Session Initiation Protocol \\ SMS & Short Message Service \\ UC & Unified Communication \\ VoIP & Voice over Internet Protocol \\ VPN & Virtual Private Network \\ VPS & Virtual Private Server \\ WAN & Wide Area Network \\ WDS & Wireless Distribution System \\ WLAN & Wireless Local Area Network \\ \end{tabular}