Front: PA1000 Packet over Sonet to HSSI Converter
Rear: PA1000 Packet over Sonet to HSSI Converter

Packet Over Sonet to HSSI

The Metrodata PA1000 converts data from byte-oriented HDLC, as used on Packet over Sonet (POS) interfaces, to bit-oriented HDLC as found on HSSI interfaces.

Packet over Sonet to HSSI Converter

  • Variable bit-rate for Packet over Sonet (POS) routers
  • Connect Packet Over Sonet (POS) core networks to legacy HSSI routers
  • Router to satellite connections at up to 90 Mbps HSSI
  • Asymmetric data rates: future-proofed satellite bandwidth
  • Hardware - based Packet rate and Interface adapter
  • Ease of migration for ISPs to develop Packet over Sonet (POS) router core within existing HSSI structure
PA1000: POS to HSSI Converter
PA1000: POS to HSSI HDLC Converter

High-speed core router networks are moving rapidly into the SDH/SONET speed stack to meet the huge demands of IP networking. Core routers are now designed to operate most efficiently over fibre, from OC-3/STM-1 (155Mbps) through to OC-192/STM-64 (10Gbps). As products, they are technically removed from the current and earlier lower-speed applications aimed primarily at HSSI and PDH Networking. As the world migrates to IP traffic, data is increasingly being transported using HDLC frames, e.g. PPP, and POS(Packet-over-Sonet/SDH).

The PA1000 serves two purposes:

  • it enables connection between a Packet over Sonet (POS) based router and a HSSI based router
  • it enables a Packet over Sonet based router to be connected to a satellite modem and to operate at data rates below 155 Mbps

The PA1000 provides a solution for satellite operators wishing to use high performance Packet over Sonet (POS) based routers for example, Juniper routers with their standard 155Mbps POS interfaces to connect to a HSSI-based network without the need to use valuable chassis slots for low speed HSSI serial interfaces. The user thereby gains a migration path - to use the router on <=52Mbps initially, and later upgrade his access speed to full STM-1 155Mbps later, without any hardware change to the router. In addition, the PA1000 supports non-standard data rates and asymmetric operation, thus providing a flexible solution for the user.

The PA1000 rate-adapts by stripping flags out of the data stream and transporting only the actual packet data. It is transparent to packet payload and may operate with any protocol that both the Packet over Sonet (POS) and HSSI devices support, such as PPP and Frame Relay.

The PA1000 provides the system integrator with a simple, convenient and economic solution for the interconnection of modern high speed routers fitted with Packet over Sonet (POS) interfaces and older legacy routers with HSSI interfaces.

There are three models in the range:

  • PA1000/MM HSSI to multimode Packet over Sonet (up to 5km)
  • PA1000/MM HSSI to singlemode Packet over Sonet (up to 30km)
  • PA1000/MM HSSI to long haul singlemode Packet over Sonet (up to 70km)

The PA1000 Packet over Sonet port operates over 5km using multimode fibre, or either 30km or 70km using singlemode fibre. Despite these quoted maximum operating distances for the PA1000 products, specific installations may only operate over lower distances due to the variations in losses of different types of fibre cable, the use of connecting fibre cables, or patch panels. When operating over 50% of the maximum distances it is advisable to calculate all fibre optic connector and cable losses and compare these with the fibre optic loss budget specified for this product.

The standard PA1000 is supplied with SC fibre connectors and operates at a nominal wavelength of 1300nm. Other wavelengths are available on request, e.g. 850nm, 1550nm, 1550/1300 WDM. Other connector options are also available on request, e.g. ST, FC.

PA1000 connecting a POS router to a HSSI satellite modem
Connecting a Packet over Sonet to a HSSI satellite modem

This application shows how PA1000 units can be used to enable a Packet over Sonet router to connect to a HSSI satellite modem.

PA1000 connecting a POS router to a HSSI router
Connecting a Packet over Sonet (POS) router to a HSSI router

This application shows how a PA1000 can be used to connect between a Packet over Sonet router and a HSSI router

Interface Type HSSI
Connector 50 way miniature AMP (SCSI-2)
Mode DCE - DTE
Data Rate DCE Mode: 51.84Mbps
DTE Mode: up to 100Mbps
Framing Mode HDLC (bit mode)
Max packet size 4096 bytes
Flags Supports back to back frames with 1 flag between frames
Fibre Port
Interface TypeFibre
Connector Duplex SC
Fibre Types Multimode (MM)
Singlemode Short Haul
Singlemode Long Haul
Data Rate 155Mbps per G.957
Payload HDLC (byte mode)
Max packet size 4096 bytes
Flags Supports back to back frames with 1 flag between frames
Compliance & Approvals
Safety EN41003, E60950
Temp 0 - 50 deg C
Humidity 0 - 95% RH, non-condensing
Pressure 86 - 106 KPa
Power Supply
-48 VDC Supply -40 to -72 VDC, 170 - 100mA
AC Mains100-250 VAC, 50-400Hz, 65mA to 30mA, IEC connector
Power consumption 6.5 watts approx when operating
Type 1U 19 inch rack mount
Dimensions 435 x 213 x 44 mm ( W x D x H)
Part Number
Product AC Mains DC Power
PA1000/MM Multimode POS to HSSI80-05-530
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PA1000/SMSH Singlemode Shorthaul POS to HSSI80-05-531
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PA1000/SMLH Singlemode Longhaul POS to HSSI80-05-532
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Further Information

Networking The World