I've got a project on the horizon involving some old phone standards so I got myself a Tektronix / Siemens K1297 protocol tester with a 4 channel simulation board for E1 (2Mbit digital stream with 30 phone lines) and another 4 channel board for monitoring E1 and T1 (1.5Mbit). This protocol tester goes way beyond the common handheld protocol testers. It is able (designed) to test interaction between various telephony switches at telecom operators and supports many different protocols and flavours. This machine must have cost a fortune when new! The only price I've found online is over $160000 for the GPRS software.
It is a compact PC based system with VME slots. The PC is a Pentium 1 with 64MB running NT4. Actually it doesn't run that bad but it could do with more memory. I paid 130 euro including shipping.
The screen is the dimmest TFT screen I have ever seen (later more about that):
The E1 interface board:
Look at that fat 68040 processor and extra goodies. Handling four 2Mbit streams with a protocol stack is not a small task.
There is also an extra board to offload the PC's processor:
Another 68040 and the Cypress chip in the bottom right corner is a VME controller.
I did play around a bit with this machine to see what it can do. My main interest is creating calls between two E1 ports which is a rather mundane task. I managed to get the links up and get a test scenario going but unfortunately the documentation is very poor. The manual literally refers to the online help for precise information on how to operate it! Still it seems this machine can do a lot and for just ISDN alone it supports many different flavours. The downside is the poor screen and loud fans or hard drive (either way it makes a lot of noise). Normally I would have taken it apart, cloned the hard drive to have a backup and cleaned it up a little. However in this case I also spotted a much newer one on Ebay with a much faster PC (with USB ports) and working screen so I decided to grab that one too for a similar amount. I'll just swap the E1 simulation board over and hopefully I'll have a much nicer system with less effort and spare parts as a bonus.