RAD IMX-2T1/E1 T1 Inverse Multiplexer

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RAD IMX-2T1/E1 T1 Inverse Multiplexer


  • Inverse multiplexing of a standard E1 frame on two T1 links

  • Complies with:

  • ITU Rec. G.703, G.704, AT&T TR-62411, TR-54019, ANSI T1.403

  • AT&T ACCUNET Fractional T45 Service

  • Several timing options

  • Compensates for differential delay

  • Control via front panel or ASCII terminal / Telnet

  • Telnet using SLIP protocol

  • Inband remote management

  • Data port supporting n x 128 kbps

  • Fractional T1 port supporting n x 128 kbps

  • Transparent to E1 timing

  • Built-in CSU on the T1 links

  • Call-in and call-out functions

  • Built-in BERT and loopbacks


The IMX-2T1/E1 enables E1 equipment to utilize two T1 transmission links by converting any E1 frame (2.048 Mbps) into two T1 frames  (1.544 Mbps). The E1 frame (256 bits) is equally divided between both T1 frames. IMX-2T1/E1 is transparent to the E1 framing pattern. It can be ordered with or without CSUs. Optional drop- and-insert G.703 or n x 56/64 kbps ports enable full bandwidth utilization by using the remaining T1 timeslots for additional traffic.

The IMX-2T1/E1 compensates for any differential delay of up to 64 msec between the T1 lines, to properly reconstruct the original stream. The end- to-end delay is not more than the maximum differential delay between the links.

Diagnostic features include:
- local/remote DTE loopback
- local/remote T1 loopback
- built-in BERT V.52

In addition, the IMX-2T1/E1 supports the T1 network loopback per AT&T 62411 (in-band  code activated), and statistical diagnostic capability according to AT&T PUB 54016.

The IMX-2T1/E1 complies with TR-54019 (E1 Access over T1 Networks).

The IMX-2T1/E1 is compatible with the DXC-M/DIM module.

Diagnostics can be initialized via the front panel or by using an ASCII terminal connected to the supervisory port.

T1 Interface

Number of links: 2

Compliance: ITU Rec. G.703, G.704; AT&T TR-62411, TR-54019, PUB 54016

Data rate: 1.544 Mbps
Line code: AMI or B8ZS

Receive level:

0 to -34dB/with CSU
0 to -10dB/without CSU

Transmit level:

0 dB, -7.5dB, -15dB/with CSU
3V ( ?} 10%) soft-adjustable to be measured at 0 to 655 ft with or without CSU

Impedance: 100 . , balanced
Framing: D4 or ESF
Connector: RJ-48C, 8-pin

E1 Port

Compliance: ITU Rec. G.703, G.704, G.823

Data rate: 2.048 Mbps
Line code: HDB3
Framing: any E1 frame


120 . , balanced
75 . , unbalanced

Signal level:

Receive level: 0 to -10 dB

Transmit pulse:

Balanced: ?} 3V ( ?} 10%)
Unbalanced: ?} 2.37V ( ?} 10%)


8-pin RJ-45 for balanced
Two BNC coaxial for unbalanced

. Data Port

Data rate: n x 128 kbps (where n=1...7), up to 896 kbps

Interfaces and connectors:

V.35 with 34-pin connector
RS-530 with 25-pin connector
V.36/RS-449 with 37-pin connector (using RS-530 port, via supplied conversion cable)
X.21 with 15-pin connector

Ethernet 10BaseT with shielded 8-pin RJ-45 connector


DCE or External DCE, user-selectable

Fractional T1 Port


AT&T TR-62411, ITU Rec. G.703, G.704

Data rate: n x 128 kbps (where n=1...7), up to 896 kbps

Line code: AMI

Receive level: 0 to -10 dB

Transmit level:

3V ( ?} 10%) soft-adjustable to be measured at 0 to 655 ft

Framing: D4 (SF) or ESF
Impedance: 100 . , balanced
Connector: RJ-48C, 8-pin

Control Signals

CTS Follows RTS or constantly ON, soft selectable

DSR Constantly ON unless in test mode

DCO Constantly ON unless in red alarm



AT&T TR-54019


Loopback timing: Link 1 or 2
Internal timing: ( ?} 32 ppm)
Station Clock timing
External E1 timing
Transparent timing
External fractional T1

Station Clock Interface

Bit rate: 1.544 Mbps
Line code: AMI/B8ZS
Impedance: 100 .
Pulse shape: ITU G.703
Connector: RJ-48C, 8-pin


framed/unframed "all ones"

T1 Differential Delay

Up to 64 msec


Local/remote E1 loopback
Local/remote T1 loopback
Local/remote fractional T1 or data port loopback

Inband code activated loopback per data port or fractional T1 according to ANSI FT1 RDL (T1E1-2/93-003)

BERT V.52, built-in

Code activated network loopback per AT&T 62411 (ANSI T1.403)

Statistics and Alarms

Full statistical diagnostics
ANSI T1.403-1989

Local support of ESF diagnostics according to AT&T PUB 54016

Alarm buffer size: 100 events

Alarm Response

Received impairment on T1
T1 response: Yellow Alarm
E1 response: AIS signal
Receive unframed "all ones" on E1
T1 response: none
E1 response: Alarm

Supervisory Port

Interface: V.24/RS-232, async
Connector: 9-pin D-type, female
Speed: 0.3 - 9.6 kbps, autobaud

Front Panel Controls

LCD (2 rows x 16 characters)
Push-buttons (Cursor, Scroll, Enter)


T1 (per link): Red and Yellow alarms
E1 port: RD, TD
Data port: DCD, RTS, RD, TD, TEST


Height: 4.4 cm / 1.7 in (1U)
Width: 43.2 cm / 17.0 in
Depth: 24.2 cm / 9.5 in
Weight: 2.3 kg / 5.0 lb

. Power Supply

115/230 VAC
-48 VDC; 18.5W




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