Single modular stand alone port for E1 DSU/CSU



E1 DSU/CSU with wide variety of user interfaces

  • User-selectable transmission rates via selected E1 timeslots.
  • Fractional E1 and Unframed E1 service
  • Operating range up to 2km (using 22AWG) and integral multiples of 64kbps, up to a maximum 2.048Mbps (unframed)
  • Built-in BERT with V.54 diagnostics
  • Unused time slots can insert IDLE code (in frame mode).


E1 DSU/CSU with variety of serial interfaces

The ETU011 stand-alone DSU/CSU is a digital access unit for Unframed E1, Fractional E1, or Fractional cascaded E1 service.The ETU011 data channel supports user-selectable transmission rates via randomly selected E1 timeslots, which provides integral multiples of 64kbps, up to a maximum 2.048Mbps (unframed), for a line attenuation of up to 43 dB on twisted pair or coax cable. This provides an approximate operating range up to 2km (using 22AWG). The ETU011 packs the data channels into the E1 link in user-selected time slots. The unused time slots can insert IDLE code (in frame mode).The ETU011 front panel sports status LEDs for monitoring both the CSU and DSU conditions and push button switches for initiating local and remote loopback with integral BERT. 


Item Description
G.703 E1

Framing Framed CCS (PCM31) CAS (PCM30)/
Unframed CRC4 on/off
Line Code AMI/ HDB3
Bit rate N×56K or N×64Kbps, where N=1~31 in
CCS or N equal 1~30 in CAS
Relative receive
level -43dB
Transmit level:
Pulse Nominal 2.37V ±10% for 75 ohm
Amplitude Nominal 3.00V ±10% for 120 ohm
Zero amplitude ±0.1V
Jitter performance According to ITU-T G.823
Connectors BNC(unbalanced), RJ-48(balanced)


LEDs (Power, TD, RD, RTS, DCD, Signal loss, Sync loss, Alarm)


ITU-T G.703/G.704/G.706 & G.732

Power Input

AC: 90-250VAC, DC: -18 ~ -75VDC

Power Consumption



250 × 195 × 45 mm (D × W × H)




0°C ~ 50°C (Operating), -10°C ~ 70°C (Storage)


10 ~ 90% non-condensing




57,000 hrs

Ordering Information

Order Code Description
CT-ETU011- A C Built-in AC 90 ~ 250 V
CT-ETU011-DC Built-in DC -18 ~ -72V
CT-ETU011-R-A Rack Mount unit with built-in AC 90 ~ 250 V
CT-ETU011-R-DC Rack Mount unit with built-in DC -18 ~ -72
CT-ETU/TTU-V35 X.21 interface module
CT-ETU/TTU-530 RS-530 interface module
CT-ETU/TTU-449 RS-449 interface module
CT-ETU/TTU-232 RS-232 ASYN/SYNC interface module
CT-ETU/TTU-G64 G.703 64Kbps co-directional interface module
CT-ETU/TTU-NRZ NRZ interface module (4×BNC)
CT-ETU/TTU-ET100 10/100 Base-Tx Ethernet E1 Bridge interface module
CT-ETU/TTU-ET100R 10/100 Base-Tx Ethernet Routing interface module

More Information