Toshiba Strata Dk14, Dk40i, Dk424i General Description Manual

							Strata DK424i
Functional Block Diagrams
Strata DK General Description    6/0035
Functional Block Diagrams
The Functional Block Diagrams show the PCBs and interface connectors used for connecting the 
stations and peripherals (see Figures 12~14).
Figure 12 KSU Processor and Optional Interface PCBs
Data and Speech Highway
25-pair
or
Terminal Strip(N/A RSSU)
5210
IMDU
B_C_U
Micro-
Processor
(68000 or 68020)
Flash
or
RAMProcessor PCB
(Optional)
PCM
Switch
System
Tones
Switch
DTMF
Receiver
(4~24 ckts.)
Conf
Switch
BRCS
Twisted
Pair
Music Source: External Zone Page
Background Music
Door Lock or BGM Mute Control Relay
External Zone Page Relays (4 Zones)
External Page Amplifier (600Ω Output)
Music Source: Background Music 
and/or Music-on-hold
MOH/BGM
Volume 
Control
Main Distribution
Frame (MDF)MOH/BGM
RCA Jack
Alarm Relay Sensor
Night Bell or MOH (Control Relay)
Battery Charger12V
Battery
12V
BatteryTwisted Pair
1.  Customer-supplied equipment.
RKYS
Option Key
AA/ACD/MIS
(2 or 4 Batteries)
CBRUKABR Tone
Detector
(Standard)
BPSU672Cabinet 
Power Supply
ROM
1200 bps Modem
RSSU/PIOU/PIOUS/PEPUSingle Serial Port (N/A PEPU)
SMDR Port (N/A RSSU/PEPU)
RSIU Serial Interface PCB (1 Port)
RSIS/RMDSSerial/Modem (2400 bps)
Interface  PCBs ( 1~3 Ports)
Programmable Serial Port
Modular Jacks or Remote Modem HMIS
SMDI
Voice Mail DKi Admin PC1
Insight DK, 
Call Center
Viewer &
ACD/MIS
 PC1SMDR
Call Accounting
Device or Printer1
Amplified Page Output (3 Watts)1
1
1
1
1
1
1
1 
						

							Strata DK424i
Functional Block Diagrams
36Strata DK General Description    6/00
Figure 13 CO Line Side Functional Block Diagram
RDTU2•2T1 / DS1(24 Channels / Lines)
•Loop Start, Ground Start, Tie, DID
•Digital Voice Lines Channel
Service
Unit (CSU) 25-pair Amphenol
TOSHIBA NDTU Cable
DB15
PLL Synchronization Circuits
2
RCOU4 Loop Start Co Lines (Analog)
RGLU24 Loop or Ground Start CO Lines (Analog)
RCOS (Optional PCB on RCOU Only):4 Loop Start CO Lines (Analog)
RCIU2
RCIS4 Caller ID Circuits
4 Caller ID Circuits
(Two 4-Wire Modular Jacks)
MDF(Two 4-Wire Modular Jacks)
(Two 4-Wire Modular Jacks)(Two 4-Wire Modular Jacks)
(Two 4-Wire Modular Jacks)
1
RDDU4 DID CO Lines (Analog)
REMU4 E&M Tie Lines (Analog)  (REMU, Four 8-Wire Modular Jacks)(Two 4-Wire Modular Jacks)
Secondary Protectors2
RPTUISDN PRI (23B+1D channels)
Digital Voice/Data Toshiba RPRI-CBL-KIT
Channel
Service
Unit (CSU)8-wire Modular Jacks
2
ISDN BRI (U)
2 Circuits (NT-1 )
Voice/Data  (2B+D)RBUU
RBUSISDN BRI (U)
2 Circuits (NT-1)
Voice/Data  (2B+D) U
4
U48-wire Modular Jacks
8-wire Modular Jacks
3
3
ISDN BRI (S/T)
2 Circuits (TE)
Voice/Data  (2B+D)RBSUNT1 per circuit2
U4T48-wire Modular Jacks
RMCUTrunk Circuits for E911
RCMS    2 Trunk Circuits
RCMS    2 Trunk CircuitsCAMA Line (2-wire Modular Jacks)
CAMA Line (2-wire Modular Jacks)
Network Demarcation Point Remote Location(s) Remote Location(s)
BVPUVoice Over IP Unit (4 Circuits)
PDKU RRCU
Remote Cabinet Interface Card
Optical Fiber Cable 3 km/(1.86 mi.) Expansion 
Cabinets
Digital
Telephone10BaseT
Router
MCK
ExtenderMCK
Gateway
IP Network
4272
Central Office 
Centrex
PBX
Common Carrier
Other Telephone System
E911 Public Safety Answer
Point (PSAP) •
•
•
•
•
•
1.  RCIU2/RCIS tip/ring cross 
connected to RCOU, RCOS, or 
RGLU tip/ring at MDF.
2.  Customer-supplied equipment.
3.  RBUU/RBUS (Release 4.3).
4. U, S, T, R are ISDN reference      
    model termination points.
Data and Speech Highway 
						

							Strata DK424i
Functional Block Diagrams
Strata DK General Description    6/0037
Figure 14 Station Side Functional Block Diagram
S4R4
S4
U4
U4
RATU4 Attendant Console Circuits
RBSU3
2B+1D/Circuit
(2-NT Circuits)
RBUU3
2B+1D/Circuit
(2-LT Circuits)
1 1 1 1
1 1 1
1
EOCU(Option PCB
to Receive
Speaker OCA)
RDSU4 Digital Telephone Circuits
2 Standa rd Telephone Circuits
PDKU28 Digital Telephone Circuits
RWIU32 Digital Wireless Telephone Circuits
RSTS(Option PCB)
2 Standard 
Telephone 
CircuitsR48S(Option PCB,
RDSU/RSTU2
Only) -48 Volt
Loop Supply
R48S(Option PCB,
RDSU/RSTU2
Only) -48 Volt
Loop Supply
PESU4 Electronic Telephone Circuits
2 Standard Telephone Circuits
EOCU(Option PCB
to Receive
Speaker OCA)
RBSS2B+1D/Circuit
(2-NT Circuits)
RBUS2B+1D/Circuit
(2-LT Circuits)
Data and Speech Highway
Digital Telephone (DKT)
and Add-on Module
Digital Telephone
with RPCI-DI
DDCB Digital Cordless
Telephone
MDFB
Door Phones and
Lock Controls TAPI PC
Modem
(Pool)DIU-DS
Mainframe Computer
DIU-DS
DIU-DSRS-232 Cables
Printer (Sharing)Digital Telephone
with DSS Console 1 Pair Modular Cord
RS-232 Cable
PC
1-pair Modular Cords
DPFTVoice
Mail
Base Station 1 Strata AirLink Wireless
Base Stations (4)
Handsets Handsets
Base Station 2 ModemRS-232 Cables
HESB
Loud
Ringing Bell Strata AirLink Base Station
Interface Adapter (BSIA)
Electronic 
Telephone (EKT)
Door Phones and
Lock Controls Standard
Telephone
Alternate BGM 
source to stations 
and Page Output
Modular Jacks
Main Distribution Frame (MDF) 25-pair Amphenol Connectors and 
Cables (except RBSU/RBSS)
PC Attendant
ConsoleEKT with HDSS Console
(PEKU Only) Power Failure
Transfer UnitPower Failure
Standard Telephone (8 max.)
Off-premises Station Digital Annuncer
for ACD and Auto Attendant
Secondary
Protector
1.  Customer-supplied equipment
2.  RSTU2 is required for standard telephone message waiting lamp.
3.  RBUU/RBUS (Release 4.3).
4.  U, S, T, R are ISDN reference model termination points.FAX
HDCB MDFB
4250
2
RSTU2 8 Standard
Telephone Circuits
PEKU 8 Electronic
Telephone Circuits
PC
ISDN
Telephone
(TE-1, S-Type)COM Port
ISDN
Telephone
(TE-1, U-Type)PC with
Video Card
(TE-1, U-Type) Digital Single Line
Telephone (DKT)
TA
123
456
789
0#abc
ghi jkl mno
pqrs tuv
operwxyzdefHOLDMSG CNF/TRN MUTE talk
chanvol 
						

							Strata DK424i
Maintenance and Programming
38Strata DK General Description    6/00
Maintenance and Programming
Hardware maintenance and repair procedures describe how to quickly locate, remove, and replace 
defective parts and PCBs. System programming can be performed without taking the system out-
of-service.
On-site programming can be executed with any 20-button proprietary LCD telephone or with a 
DKi Admin PC connected to an optional maintenance port. Off-site programming with DKi 
Admin is available through a customer-provided modem connected to the maintenance port.
DKi Admin/DKi Backup
Toshiba DKi Admin software Release 4.3.1 and higher, enables customer data (configuration, 
station, and system options) to be downloaded to a PC and stored on a computer disk. The new 
customer data can then be uploaded to the DK System from the PC, changing customer program 
options on-site or remotely over telephone lines and/or modems.
The DKi Backup software is also available. DKi Backup consists of a subset of DKi Admin 
functions such as backup, restore and upgrade functions, but it cannot edit customer databases.
StrataControl
StrataControl is a Windows-based PC application enables limited access to Strata DK40i and 
DK424i system programming functions. See “StrataControl” on Page 89 for more information. 
						

							Strata DK General Description    6/0039
Universal Slot PCBs4
This chapter describes each of the PCBs that install into the universal slots of the Strata DK40i 
Expansion KSU, the DK424i Base/Expansion Cabinets. The following paragraphs categorize the 
cards according to their function.
Descriptions here apply to both DK40i, DK424i unless noted otherwise. The DK14 does not 
support any universal slot PCBs. 
Feature subassemblies that plug onto a universal slot PCB, such as the Standard Telephone 
Interface Subassembly (RSTS), are listed below the associated PCB. For a list of available 
subassemblies, see Table 28 on Page 45.
Station PCBs
Digital Telephone Interface Unit (PDKU2)
The PDKU2 has eight digital telephone circuits that can support digital telephones (cordless as 
well as corded), integrated PC interface data units for data calling and/or TAPI application, off-
hook call announce, DDSS consoles or DADMs for attendant stations that must handle a heavy 
load of calls, and a DDCB for a variety of applications. 
Each of these devices only requires one circuit except for the integrated PC interface unit or 
DADM, which shares a circuit with the telephone to which they are connected.
Digital/Standard Telephone Interface Unit (RDSU)
The RDSU in its basic configuration has two standard telephone circuits and four digital telephone 
circuits (cordless as well as corded). The standard telephone circuits can support the same devices 
that the RSTU2 can, with the exception of standard telephone message waiting lamps. 
The digital circuits can support the same devices as the PDKU, except for the DDSS console. The 
RDSU can be equipped with an RSTS subassembly to provide two more standard telephone 
circuits, and an R48S subassembly to increase the standard telephone maximum loop length.

DK40i – a K5RCU or K5RCU2 must be installed in the Base KSU to interpret DTMF tones 
transmitted by devices connected to the standard telephone circuits.

DK424i – a BRCS must be installed on the main processor PCB to interpret the DTMF signals 
for devices connected to the standard telephone circuits. 
						

							Universal Slot PCBs
Station PCBs
40Strata DK General Description    6/00
Standard Telephone Interface Subassembly (RSTS)
The RSTS attaches to the RDSU and adds two standard telephone circuits to the PCB. With the 
RSTS installed, the RDSU provides four standard telephone circuits and four digital telephone 
circuits. (RSTS does not support standard telephone message waiting.)
Strata AirLink Wireless Interface Unit (RWIU)
The RWIU interfaces the DK40i, DK424i with the Strata AirLink Telephone wireless system. The 
card functions as a protocol converter between the Base Stations and the PBX. It has four digital 
circuits that connect to four Base Stations using industry standard RJ11 jacks. Roaming and 
handoff functionality are present between all four Base Stations.
CO Line/Digital Telephone Interface Unit (KCDU) (DK40i only)
The KCDU provides two analog loop start CO line circuits and four digital telephone circuits. The 
CO line circuits offer all of the features that the Base TCOU and the RCOU line circuits provide. 
The digital telephone circuits can support every peripheral (except for the DDSS console) that the 
PDKU2 and a Base KSU digital circuit can support. Up to four KDCU PCBs can be installed in 
the DK40i Expansion Unit.
NoteThe RCIU2 Caller ID Interface Unit is required to add Caller ID with the KCDU PCB.
Electronic Telephone Interface Unit (PEKU)
The PEKU provides eight electronic telephone circuits that can interface with electronic 
telephones, an alternate BGM source, a Direct Station Selection Console (HDSS), an external 
amplifier for DISA or two-CO line Conferencing. 
Standard/Electronic Telephone Interface Unit (PESU)
The PESU offers two standard and four electronic telephone circuits. Its standard circuits support 
the same devices as the KSTU2. Its electronic circuits interface with the same peripherals as the 
PEKU, except for the HDSS console. 

DK40i – a K5RCU or K5RCU2 must be installed in the Base KSU to interpret DTMF tones 
transmitted by devices connected to the standard telephone circuits.

DK424i – a BRCS must be installed on the common control unit to interpret the DTMF 
signals for devices connected to the standard telephone circuits.
Off-hook Call Announce Upgrade Unit (EOCU)
Electronic telephones connected to PEKU and PESU PCBs can receive speaker Off-hook Call 
Announce (OCA)—internal [DN] calls over their speaker while they are on another call—if the 
PCBs are equipped with an EOCU. Digital telephones also support this function, but do not require 
an EOCU in the KSU. Unlike digital telephones, electronic telephones cannot receive handset 
OCA.
Standard Telephone Interface Unit (RSTU2)
The RSTU2 has eight circuits that can support single-line devices (one device per RSTU2 port). 
Besides rotary and DTMF standard telephones, the RSTU2 can support the Strata AirLink 
Wireless analog system, fax machines, dictation equipment, modems, a separate BGM source, off-
premises stations, Toshiba Stratagy and VP voice mail systems, and digital announcement devices 
for optional built-in AA or ACD. 
						

							Universal Slot PCBs
Console PCBs
Strata DK General Description    6/0041
This PCB also supports the Message Waiting feature on standard telephones that are equipped with 
a 90VDC neon message waiting lamp.
The RSTU2 also provides an 80V RMS sine wave ring generator and has interface connectors for 
an optional R48S subassembly that increases the maximum possible station loop length from 600 
to 1200 ohms.

DK40i – a K5RCU or K5RCU2 must be installed in the Base KSU to interpret DTMF tones 
transmitted by devices connected to the standard telephone circuits.

DK424i – a BRCS must be installed on the main processor PCB to interpret the DTMF signals 
for devices connected to the standard telephone circuits.
48V Loop Voltage (R48S)
The optional R48S unit can be connected to the RSTU2 or RDSU and, by creating 48V loop 
voltage instead of 24V, can extend the maximum possible loop length of standard telephone 
circuits (including the resistance of the phone) from 600 ohms to 1200 ohms, allowing standard 
telephones to be connected farther from the system. By using this unit, a less expensive type of off-
premises lines can be used (see Table 28 on Page 45). 
Console PCBs
Attendant Console Interface Unit (RATU, DK424i only)
The RATU can support four attendant consoles. Multiple consoles enable automatic load-sharing 
on a rotation basis from a central call queue, increasing call handling efficiency. The RATU PCB 
in the Strata DK424i system cabinets connects to the PC Attendant Console Interface (RATI) via 
two pair of wires.
One RATU is available per system to support a maximum of four Attendant Consoles per system 
with B5CAU/B5CBU, two with B2CAU/B2CBU or B3CAU/B3CBU (any combination of PC or 
conventional consoles).
CO Line PCBs
A summary of Strata DK station, CO line PCBs and feature subassemblies are listed in Table 28 on 
Page 45.
Caller ID Interface Unit (RCIU2)
The RCIU2 is required, along with an analog ground/loop start CO line PCB, to provide the Caller 
ID feature. Caller ID is also known as CLID and is available at extra cost per line from the local 
Telco. It is sometimes known as a CLASS feature.
Each RCIU2 circuit receives and decodes telephone number and name information sent from the 
calling CO. Caller ID is available on analog loop start lines and analog ground start lines only. An 
RCIU2 circuit must be available with each RGLU2, RCOU/RCOS, PCOU or KCDU2 circuit that 
is to receive Caller ID. Built-in gas tubes help protect each RCIU2 circuit from lightning surges.
An RCIS subassembly PCB can be installed onto the RCIU2 to provide four additional Caller ID 
circuits.
Caller ID Interface Subassembly (RCIS)
The RCIU2 comes equipped with four Caller ID circuits; an RCIS subassembly PCB can be 
installed onto the RCIU2 to provide four additional Caller ID circuits. Hence, an installed RCIU2/ 
						

							Universal Slot PCBs
CO Line PCBs
42Strata DK General Description    6/00
RCIS can provide a maximum of eight Caller ID circuits per cabinet slot. Built-in gas tubes help 
protect each RCIU2/RCIS circuit from lightning surges. 
Loop Start CO Line Interface Unit (RCOU)
The RCOU in its basic configuration has four analog loop start CO line circuits, connecting to the 
public telephone network. 
Each RCOU line can be programmed for DTMF or Dial Pulse signaling and has a switch to control 
potential excess volume that can be created by a nearby PBX or CO. 
An optional RCOS subassembly can be attached to the RCOU for four more loop start lines. Each 
line can be programmed for DTMF or Dial Pulse signaling. Built-in gas tubes help protect each 
circuit from lightning.
Loop Start CO Line Interface Subassembly (RCOS)
The RCOS can be attached to the RCOU to provide four additional analog loop start CO line 
circuits. Each RCOS line has all of the features that are available with the RCOU lines.
Ground/Loop Start Interface CO Line Interface Unit (RGLU2)
The RGLU2 provides four analog CO line circuits which can be configured individually for 
ground start or loop start. Ground start should be used for applications requiring disconnect 
supervision, such as AA/Voice Mail, or ACD.
The RGLU2 also provides ring detection, dial outpulsing, Hold, and CO line flash signal. Each 
RGLU2 line can be programmed for DTMF or Dial Pulse signaling and has a switch to control 
potential excess volume that can be created by a nearby PBX or CO. Built-in gas tubes help protect 
each circuit from lightning.
Direct Inward Dialing Interface Unit (RDDU)
The RDDU provides four analog DID lines, each of which is assigned a single office code along 
with a block of extension numbers. Each extension number is programmed to ring a [DN] selected 
in system programming. This enables calls over the same line to be routed to different stations. 
Each DID line can be set for either Wink Start or Immediate Start. DID lines can also support 
DNIS and/or ANI. An optional K5RCU or K5RCU2 (DK40i) or BRCS (DK424i) tone receiver 
PCB is required for DTMF DID operation. Rotary DID signaling ability at 20 pps is a standard 
feature. An external protector is required for each line.
Tie Line Unit (REMU)
The REMU has four analog circuits for E & M Type I or Type II signaling, Immediate Start or 
Wink Start Tie lines. A choice between 2- or 4-wire transmission is available as a jumper-plug 
option.
Tie lines can also support DNIS and/or ANI. An optional K5RCU or K5RCU2 (DK40i) or RRCS 
(DK424i) tone receiver PCB is required for DTMF Tie operation. An external protector is required 
for each line. REMU Tie lines are two-way and can be used for incoming and outgoing calls. 
						

							Universal Slot PCBs
CO Line PCBs
Strata DK General Description    6/0043
Voice Over IP Gateway (BVPU)
The BVPU combines the functions of a four-circuit REMU E&M Tie line card and a Voice Over 
Internet Protocol (IP) gateway on a single PCB. The BVPU is an H.323 Version 2 compliant 
gateway and can interoperate with other H.323 devices as well as other BVPUs. The BVPU allows 
multiple Strata DKs to establish virtual Tie line connections across an IP network. The BVPU 
connects to the LAN through an RJ45, 10BaseT connection. An RJ21 jack provides a serial 
maintenance connection.  This connection must be used to initiate the card.  Once an IP address 
has been established, maintenance may be performed through the LAN connection.
T1/DS-1 Interface Unit (RDTU2)
The RDTU provides either 8, 16 or 24 digital voice channels that can be individually configured 
for ground start CO line operation, loop start CO line operation, DID/DOD line operation (with 
hookflash) or Tie line operation (8 or 12 on DK40i). The number and type of channels for each 
RDTU installed is assigned in system programming.  All RDTU line types are two-way and can be 
used for incoming and outgoing calls.
Any RDTU, DID/DOD, or Tie channel can be configured in system programming to receive DNIS 
and/or ANI information from long distance carriers.
The RDTU normally requires the installation of a Channel Service Unit, which is not supplied by 
Toshiba. RDTU T1/DS-1 digital voice channels can be configured for SF or ESF format and either 
AMI or B8ZS line coding (see Table 28).
The RDTU2 supports the hook flash capability. “SuperTrunk” requires hook flash operation on T1 
two-way DID/DOD lines. The RDTU1 can be upgraded to support hook flash.
In most locations within the U.S., network connection using RDTU2 requires a dealer-supplied, 
UL-listed external CSU or in Canada, a CSA-certified CSU.
ISDN Primary Rate Interface Unit (RPTU)
The Primary Rate Interface Unit is a 24-channel PRI card, which provides 1 data (control) channel 
and 23 bearer channels. All B channels appear and program as CO lines in the DK424i systems 
and can be individually configured for local service, FX, WATS, DID, Tie, etc., service operation. 
Network connection using the RPTU requires a dealer-supplied, UL-listed, external CSU in most 
locations in the U.S. In Canada, the CSU/DSU must be CSA certified.
See “ISDN Primary Rate Interface (PRI)” on Page 79 for more information.
ISDN S/T-type Basic Rate Interface Unit (RBSU)
The Basic Rate Interface (BRI) Unit provides two BRI S/T circuits. Each circuit provides two 
simultaneous voice and/or data connections with a single interface. BRI uses the 2B+D 
transmission format which is defined as two 64-kbps bearer channels and one 16-kbps data 
(control) channel. The D channel carries call setup control data. 
The RBSU BRI circuits can be connected to ISDN BRI network lines and/or ISDN S-type 
Terminal Equipment (TE-1) or Terminal Adapters (TA) on the station side. 
The RBSU/RBSS BRI circuits that are configured for the station side provide a passive bus that 
enables up to two TE1 and TA devices to be connected to one BRI circuit. When multiple TE1 and 
TA devices are installed on a singled RBSU/RBSS BRI circuit, the devices must share or contend 
for that circuit’s two B channels. 
						

							Universal Slot PCBs
CO Line PCBs
44Strata DK General Description    6/00
A maximum of two simultaneous voice and/or data calls are allowed between all devices 
connected to the same BRI circuit. The contention rule for the two BRI B channels is first come, 
first serve. Network connections using BRI S/T type interface also require a dealer-supplied, 
UL-listed, external Network Terminal (NT-1) device. In Canada, the NT-1 must be CSA certified.
Basic Rate Interface Subassembly (RBSS)
The RBSS attaches to the RBSU to provide two additional BRI S/T type circuits that can be used 
for station-side connections only. An RBSU with the RBSS subassembly provides four BRI 
circuits in one card slot.
RBSU/RBSS stations can be voice and/or data devices, such as ISDN telephones and Terminal 
Adapters, that support the standard S-type interface. Each RBSU/RBSS circuit provides two B 
channels, plus one D channel and reduces the system’s basic capacity by two station ports and two 
CO lines. See “ISDN Basic Rate Interface (BRI)” on Page 79 for more information.
ISDN U-type Basic Rate Interface Unit (RBUU)
The Basic Rate Interface Unit provides two Basic Rate Interface (BRI) “U” circuits. Each circuit 
provides two simultaneous voice and/or data connections with a single interface. BRI uses the 
2B+D transmission format which is defined as two 64-kbps bearer channels and one 16-kbps data 
(control) channel.
Basic Rate Interface Subassembly (RBUS)
The RBUS attaches to the RBUU to provide two additional BRI “U” circuits that can be used to 
connect to Network BRI lines and/or station-side connections only. An RBUU with the RBUS 
subassembly provides four BRI “U” circuits in one card slot.
RBUU/RBUS stations can be voice and/or data devices, such as ISDN telephones and Terminal 
Adapters, that support the standard U-type interface. Each RBUU/RBUS circuit provides two 
B channels plus one D channel and reduces the basic system capacity by two CO lines and two 
station ports. See “ISDN Basic Rate Interface (BRI)” on Page 79 for more information.
Enhanced 911 CAMA Trunk Interface Unit (RMCU/RCMS)
The RMCU/RCMS PCBs provide up to four CAMA trunk circuits. The RMCU/RCMS eliminates 
the need for connection of adjunct terminal adapter equipment to E911 CAMA trunks. Also, see 
note below RCMS.
CAMA Trunk Subassembly (RCMS) 
One RCMS subassembly attaches to the RMCU to provide two CAMA trunk circuits. A second 
RCMS can be added to provide four CAMA trunk circuits.
NoteThe RCMS is ordered separately from the RMCU, but it must be installed on the RMCU 
to provide CAMA trunk interface.