CMX625P4 CMLMICRO [CML Microcircuits], CMX625P4 Datasheet - Page 8

• Manufacturer Part Number: CMX625P4
• Description: ISDN TA POTS Interface
• Manufacturer: CMLMICRO [CML Microcircuits]

ISDN TA POTS Interface
1.5.2
Terminal mode (TE) frame structure consists of 3 channels of 4 bytes each repeated at 8kHz, i.e. 96 bits
in 125 s or a data rate of 768kbps. The Data Clock (DCL) operates at twice the data rate, i.e. 1.536MHz.
Figure 3 shows the TE mode frame structure.
‘Channel 0’ is used for passing user data (2B+D channels) and controlling (MON0 and C/I0) the Layer 1
transceiver. Only ‘Channel 1’ is used by the CMX625. ‘Channel 2’ is reserved for D channel arbitration.
The 12 byte frame contains the following channels:
(i)
(ii) The ‘Monitor’ channels consist of two programming channels, labelled MON0 and MON1. Each
2001 Consumer Microcircuits Limited
The ‘B’ channels consist of two 64kbps data channels, labelled B1 and B2, and transfer B channel
data to and from the network.
channel consists of 8 bits of data and has two associated pair of handshake bits that control data
flow, MX and MR (monitor transmit and receive). The handshake procedure is described in section
1.5.4. The MON1 channel is used for programming and controlling devices attached to the IOM-2
interface. The CMX625 is programmed via the MON1 channel (see section 1.5.15). The MON0
channel is not used. Monitor channel contention is avoided by a “speak when spoken to” system
whereby the CMX625 is given a unique address, programmed with the 3 Slot Address pins (SA0 to
SA2) and 1 Device Select pin (DS) and only responds when that address is broadcast by the master
device (see section 1.5.14). The Monitor channel address byte is shown below:
MON Channel
Terminal Mode (TE)
FSC
DCL
DU/DD
Address
Byte
FSC
DCL
DD, DU = 768kbps
CHANNEL 0
CHANNEL 1
CHANNEL 2
= 8kHz
= 1.536MHz
Bit 7
CHANNEL 0
1
Figure 3 Terminal Mode Frame Structure
Address
Bit 6
SA2
Slot
Not Used
IC1
B1
Address
Bit 5
SA1
Slot
CHANNEL 1
Not Used
8
IC2
B2
125µs
Address
Bit 4
SA0
Slot
M
S
B
Not Used
MON0
MON1
Device
Select
Bit 3
DS
CHANNEL 2
L
S
B
D
C/I1
TIC
C/I0
Bit 2
0
M
M
R
R
M
M
X
X
Bit 1
0
Bit 0
0
CMX625
D/625/2