TEK-250

E1 Retimer / Filter - Model TEK-250

• Reconstitutes network timing accuracy
• Simple, economical retiming solution
• Eliminates timing transients
• Allows for timing of edge/remote elements
• For remote switching node timing
• Ensures effective data/call continuity
• Automatic cut-thru on failure
• Mounts in existing switch cabinet
• Rack mount optional
• 5-Year limited warranty
• CE certified
• RoHS compliant

Product Overview

In today’s evolving network topologies, edge aggregation element deployments have increased while still employing E1 network interfaces. These remote switches are connected through various transport and routing elements, rather than through dedicated copper cable. Maintaining accurate timing of edge and remote switches is therefore difficult because the timing traceability and stability can become corrupted or untraceable within these transit elements. Spectracom’s Timing Enhancement Kit (TEK™) provides a simple, economical solution to this problem.

Core and host systems accept timing references from a Synchronisation Supply Unit (SSU). Edge devices and remote switches generally do not have external clock inputs, instead deriving their timing from the host via the network E1(s). The remote acts as a slave clock following the input. This makes the stability of this element susceptible to buffer delay variations, TDMoIP variations, wander, and pointer adjustment. These timing deviations can cause the clock in the remote switch to lose sync with the core network or host element, compromising effective data/voice delivery.

The TEK-250 Retimer/Filter reconstitutes the timing accuracy and stability of the network E1. The device employs a unique line retiming buffer that ensures the E1 stream is delivered at the accuracy of the local reference. Accurate rate is established and phase transients are removed from the E1 line at the point of use. If the reference is lost, the TEK-250 reverts to its embedded filtering algorithm, ensuring E1 line continuity while mitigating detrimental transients.

Installing a TEK-250 is a simple method for reconstituting and maintaining network standard frequency for edge/remote devices that does not require specific transport network topology knowledge or assignment. The TEK is a compact, hard-wired device designed to mount inside the physical cabinet of the remote switch. Unlike external timing units, the TEK has no need for east/west coding, making the input and output designations more intuitive. This design also minimizes the risk of cascading errors caused by improper connections.

For installations external to the remote switch, Spectracom offers solutions for mounting in ETSI racks/cabinets.
 

Technical Specifications

PERFORMANCE
Digital PLLL Operation	Bandwidth 0.1 Hz (wide) or 0.005 Hz (narrow); switch-selectable
	Phase Buildout Input phase changes of ≥3.5 µsec over an interval of ≤0.1 second are absorbed by DPLL without causing ≥0.05 UI (24 nsec at E1 rate) phase change on the output (Phase Buildout). Input phase changes of ≤1.0 µsec over interval of ≤0.1 second are not built-out
Jitter Filtering	When synced to an ideal (jitter-free) signal, the output jitter is ≤24 nsec (0.05 UI at DS1 rate) peak-to-peak
Wander Transfer	When timed by an input signal whose TDEV is less than or equal to the following levels:
	Integration Time T (seconds) Input TDEV (nanoseconds) 0.05 < T < 10 100   10 < T < 1000 31.6 x T^0.5 1000 < T N/A
	The TDEV of the output signals is less than or equal to the following levels:
	Integration Time T (seconds) Input TDEV (nanoseconds) T < 0.05 N/A   0.05 < T < 0.1 1020 x T 0.1 < T < 10 102 10 < T < 1000 32.2 x T^0.5 1000 < T N/A
Reliability	Estimated MTBF > 400,000 hours
INPUTS / OUTPUTS
Power Input	Dual (A & B) –48 VDC; isolated lugs with protective covering
AMI Input & Output, Alarm Relay Contacts	RJ Connectors; alarm relay contacts rated at 2A max.
Alarm Conditions	Loss of one or both power inputs Internal failure of unit
Input Framing	Operates with either Channel Associated Signaling (CAS) or Common Channel Signaling (CCS) on E1 line.
Line Coding Selection	AMI or zero-suppression (HDB3)
Input Selection	SSU input automatically selected if signal is present and valid; if no valid SSU signal available, unit filters AMI input signal.
Output Impedance	E1: 75 ohm +/-6% or 120 ohm +/-6%, switch selectable
Output Squelching	User settlable output squelching on fault or loss of timing reference

Physical & Environmental Specifications

ELECTRICAL
Supply Voltage	-36 to -72 VDC, ± 2 VDC
Supply Current	Steady-state: 100 mA (at 48 VDC) Start-up: 250 mA (at 48 VDC)
Start-up Voltage Transients	0 V to 75 V
ENVIRONMENTAL
Operating Range	-5° C to 70° C (23° F to 158° F)
Rate of Change	+/-30° C/hour (+/-86° F/hour)
Storage Range	-40° C to 85° C (-40° F to 185° F)
Relative Humidity	95%, non-condensing
Vibration	0.008 g^2/Hz @ 5-20 Hz; 0.05 g^2/Hz @ 20-100 Hz
PHYSICAL
Size/Weight	173.0 mm W x 48.0 mm H x 102.0 mm D, 0.45 kg (6.8125” W x 1.875” H x 4.0” D, 1.0 lbs)

Ordering Information

TEK-250	E1 Retimer / Filter
Mounting	480mm/580mm (19"/23") Rack Mount Kit