A while ago, I went down the rabbit hole of trying to untangle T1 line buildouts. Information on anything related to T1 circuits seems to be mired in unclear and sometimes contradictory jargon and terminology making it difficult to get to the bottom of things at times. This page is an effort to get to the bottom of T1 line buildouts and do so in a well defined and consistent manner while referencing a variety of sources for the content on the page.
Along the way, we'll have to discuss the general arrangement of a traditional, repeatered T1 span as well as some other aspects of T1 to build the correct context for the subject.
T1 line buildout generally refers to the setting of the amplitude and pulse shape of the pulses transmitted by a T1 transmitter. In general, there are two rough classes of pulse, which I will refer to as short-haul and long-haul. The literature sometimes describes these classes of pulse as 'DSX-1' and 'DS1', but I will stick to the terms short-haul and long-haul.
Some of the information here must be framed in the context of the arrangement of T1 circuits in the real world, and as such some additional terminology to describe that becomes relevant.
A T1 office repeater is the device used in a central office to receive a T1 signal, weak from transmission through the outside cable plant, and regenerate it for use with equipment in the central office or retransmission back into more outside cable plant.
Terminal equipment is equipment which terminates a T1 span.
A Channel Service Unit (CSU) is customer premises equipment (CPE) that sits between the T1 network interface (NI) and the customer terminal equipment.
The following is a list of references with links that are used in this page as supporting information.