Appropriate Technical Solutions

The ELCT Email System

Introduction

Throughout the widespread ELCT's (Evangelical Lutheran Church of Tanzania) field of action wired communication technology structures are only partially available. For this reason radio communication systems, allowing voice communication, have been developed and operational since years. Within the closer range of Moshi VHF radio is used, whereas the nation-wide coverage relies on HF radio technology.

With the introduction of computers in ELCT services and agencies came the idea of linking them via the existing radio network in order to exchange written messages. On one hand the internal communication of these ELCT points thus was improved and by means of a suitable structure these remote points are now able to communicate with e-mail with the entire world.

Technically speaking the Mailbox systems uses the USB (Upper Side Band), whereas the voice communication is continued on the LSB (Lower Side Band). With additional timesharing, the system can be used even more effectively as data is being transmitted during the night at hours where voice communication is less frequent. This reliable technology, developed by radio amateurs is considerably cheaper than similar features realised with so called professional systems. The necessary investments of around US 7.000 $ for the set-up of the (central mailbox) system as well as the running costs are now being shared amongst the subscribers and they paid off already. Even cost recovering, this form of communication meets a real need of its users and is to be considered a very economic solution in this area lacking other alternatives.

The Mail Boxes in Moshi, Mbeya and Dar

The heart pieces of those systems are normal personal computers working as servers, situated in Offices in Moshi, Mbeya and Dar. It now fulfils automatically several functions, which basically are:

• Receiving of e-mails coming in from the Mailbox users via radio
• Sending received e-mails to the individual users via radio
• Linking by telephone dial-up connection to hand over out-going e-mails to the Internet and to receive incoming e-mails from the Internet destined for the radio users.

Whereas most of the e-mail administration is done by self-developed software the presence and intervention of an experienced system operator (who likes Linux !) is still needed.

The Users (Subscribers) of the System

Initially intended for the ELCT's services the Mailbox is now also being opened to other interdenominational users. At the beginning of 2004 some 130 users have subscribed to the system. The admission policy only allows subscribers which have no access to wired telephone networks to be admitted to the radio services. About 120 users using the telephone dialin service. Being started off as a support service for social, missionary and developmental activities of the church potential subscribers of these fields are privileged for subscription.

For radio email each user needs at his site essentially three pieces of equipment, whereof one or two are often already being used for i.e. voice communication (the radio) or office application (the computer). In this case only a suitable radio modem needs to be purchased which allows transmission of computer data (like an e-mail) over a radio communication system.  The required modems are sold for around US 600 $. The Mailbox application (text editor and e-mail management) itself does not require any special computer, it may be installed on any type of personal computer available using any standard email program.

Thomas Ahnert