The British Telecom mONARCH extension users guide, issue 1 (5/87) is a collectable item that provides instructions for using the telephone extension. This guide, produced by British Telecom, is specific to the mONARCH telephone model and offers users detailed information on how to properly use the features and functions of the telephone. The guide is a valuable resource for those looking to enhance their understanding of the mONARCH telephone system.