PageOutline = Motorola Horizon macro BTS=

The Motorola Horizon macro BTS is a BTS model manufactured by Motorola in the late 1990ies.

It can support up to 6 TRX, typically in a configuration of 3 sectors.

There is currently no support for it in OpenBSC, but we are working on it.

Hardware

=== CTU ===

The up to 6 CTU modules are the individual transceivers. They plug into the SURF RF backplane and have a front-accessible
DB9 serial port, as well as a SMA connector for the TX PA output.

This TX PA output is normally wired using a ~10cm semi-rigid SMA cable to the TX input port of a combiner.

=== Combiner ===

The combiner / duplexer combines the TX signal of two CTU and duplexes it with the Rx path in order to be able to have two TRX attached to one antenna

=== MCUF ===

The MCUF is a full-size digital board and contains the BTS controller

=== NIU ===

The NIU is a E1 interface card for up to two E1 lines. Multiple NIU boards can be plugged into the rack

=== BPSM ===

The BPSM is a small power supply for the NIU, MCUF and other digital boards

=== A-bis interface ===

The A-bis interface is via classic E1 lines. The Horizon indoor cabinet supports up to 6 E1 ports.

Each NIU module serves 1 or 2 E1 ports.

The E1 ports are physically routed to the BIB (Balanced Interface Board) module on top of the cabinet.

The pinout of the 37pin D-Sub connector on top of the BIB board has been reversed as:

	Pin		Transformer
	1		T1.1
	2		T2.1
	3		GND
	4		T4.1
	5		T5.1
	6		GND
	7		T7.1
	8		T8.1
	9		GND
	10		T10.1
	11		T11.1
	12		GND
	13		T13.1
	14		T14.1
	15		GND
	16		T16.1
	17		T17.1
	18		GND
	19		GND
	20		T1.8
	21		T2.8
	22
	23		T4.8
	24		T5.8
	25
	27		T7.8
	28		T8.8
	29		T10.8
	30		T11.8
	31
	32		T13.8
	33		T14.8
	34
	35		T16.8
	36		T17.8

Software

=== MCUF ===
There is a 20MByte Intel Series2 Flash PCMCIA card inside the MCUF. IT contains software + configuration for the BTS.