CMU Rear View 
1100.4903.12 1.9  E-10 
KEYBOARD
MONITOR
COM 1
AUX
SERVICE
IF 3  RX CH1
Input and output for Abis interface (CMU 300 only)
REF OUT 1 REF OUT 2
REF IN
REF OUT 1REF IN
IF interface
(CMU 200 only)
AUX4
I/Q CH1
IF3 RX CH1 IN
IF3 RX CH1 IN IF3 RX CH1 IN
IF3 RX CH1 IN
ABIS TX
ABIS RX
ABIS
I/Q interface
(CMU 200 only)
Balanced Abis
interface
(CMU 300 only)
 
Fig. 1-9  CMU rear view – Abis and I/Q-IF inputs and outputs 
 
Abis connectors (CMU300 with option CMU-B71)  
 
ABIS TX ABIS RX
Two 75 Ω BNC connectors for option CMU-B71, Abis 
Interface Unit for CMU (for CMU300 only):  
ABIS TX  For future extensions 
ABIS RX  Input for PCM signals from a BTS under 
test to be applied to the CMU's Abis 
interface 
 
! 
Operating manual 
CMU-K30/-K31/-
K32/-K33/-K34
 
ABIS
 
9-contact SUB-D connector with alternative 
120 Ω balanced input for Abis interface . 
 
! 
Chapter 8, 
"Hardware 
Connectors"
 
I/Q-IF Interface (CMU200 with option CMU-B17)  
 
IF3 RX CH1 IN
IF3 RX CH1 OUT
IF3 TX CH1 IN
IF3 TX CH1 OUT
Four 50 Ω BNC connectors for option CMU-B17, I/Q and 
IF Interface (for CMU200 only):  
IF3 RX CH1 IN   RX path, IF IN 
IF3 RX CH1 OUT   RX path, IF OUT 
IF3 TX CH1 IN   TX path, IF IN 
IF3 TX CH1 OUT   TX path, IF OUT 
 
! 
Chapter 4, 
"Hardware 
Connectors"
Chapter 8, 
"Hardware 
Connectors"
 
I/Q CH1
15-contact SUB-D connector for input and output of I/Q 
signals (option CMU-B17, I/Q and IF Interface, for 
CMU200 only) 
 
! 
Chapter 8, 
"Hardware 
Connectors"
Note:  The CMU is delivered with different rear panel designs, however, the names of the 
connectors are unambiguous and used irrespective of the design.