Pole Less External Plant

Introduction Conventional method of installation of phone connection in BSNL is by erection of overhead lines from the nearest cable DP. Generally 20 and 10 pr DPs are in vogue. Due to the advent of the principle of “Mission Better Communications” and introduction of jelly felled underground cables, for every three phone connections, one external DP is permitted into the conventional method followed hither to.

This system is practically found to be more faults prone due to various factors such as the quality of line materials used and the location of external DPs, which are subjected to various seasonal vagaries.

In the said scenario introduction of internal DPs inside subscriber’s building can achieve a total fault free condition.

Pole less external plant

You are aware that the external plant network comprises of underground cables, cabinet/pillars. Distribution points, drop wire laid on telephone poles, Lines Jack unit, telephone instruments etc. the pole less external plant means that the outdoor plant network is free from the pole alignments and its allied components.


Reduction in fault rate has always been a serious concern to the Telecom Department. In this connection during 80s and early 90s, all the electro-mechanical exchanges were replaced by electronic exchanges in phased manner in internal plant. The fault rate improved to some extent only as the performance of the external plant has not kept pace with it.

You are aware during last two decades there had been tremendous growth in the telecom network. Over the years large number of new connections have been added to the network. The number of new connections have been added specially in the last three or four months of the year, majority of which do not confirm to standard quality norms.

The drop wire constitutes the last link in the communication network from the DP to subscriber premises. This is generally a single pair PVC insulated wire, designed for continuous out door units.

Earlier cadmium copper drop wire of diameter 0.9 mm was in use in the Telecom network. But thereafter, self supporting drop wire (SSDW) of diameter 0.5mm was developed with a view to economise on copper. But there have been field complaints on this drop wire from number of Circles. Most of the complaints related to the poor quality of insulation of breaking of conductor. There was also termination problem of these drop wires in Distribution Point (DP).

A High Committee was formed in 1997 to review the reasons for high fault rate in external plant. The problems of drop wire DPs and telephone instruments were reviewed and following recommendations were implemented