This is launching my new series that will probably drop off after 2-3 iterations, so we’ll see how far I get! Anyways the idea behind “junk of the week” is just to briefly talk about some random item, usually a piece of tech gear, but the item will hopefully be unusual and/or something the average Joe doesn’t see every day.
In this case, its the Ameritec Crescendo CRS-D call generator. This was a splurge ebay purchase where the shipping was most of the purchase. You can find a really dense marketing brochure for this thing here: Marketing Brochure
This device was used in telecom “central offices” to generate artificial phone traffic (IE: calls) to test switches, wiring, and other telco infrastructure. They come in a variety of types, this one being a large-scale T1 unit. This unit supports up to 8 T1s, so with each T1 having 24 channels, it can generate up to 192 simultaneous calls at once. I’ve been working a lot with T1s (DS1/T-Carrier, or whatever you want to call it) in a phone lab I’ve been putting together for fun, so I thought this monstrosity would be cool to test-drive things in the lab. In hindsight, I think the funds would have been better towards a T1 card for an Asterisk box, but thought it would be fun to mess with this.
As such with buying random junk on ebay, its always a gamble, despite having a lot of luck overall. In this case, I believe this unit may be a miss versus a hit, and I’ll mention why below. Regardless, its still fun to research stuff, but better to do more research first before hitting the buy button.
Taking a Look Around
Upon arrival, I noticed this guy to be a lot larger than I thought; it’s a full 4u rack unit that might actually be for a 23″ telecom rack as opposed to a standard 19″ rack. On the front of the unit as pictured above, there’s an LED panel with status lights for 8 T1 circuits. In the center, there’s a few LEDs that appear to relate to System7 signalling. The bottom of the front panel has a purple-ish “hot pink” vent looking panel that definitely popular in the 90s, but maybe a little unusual for telecom gear. It reminds me of SGI (Silicon Graphics) gear a bit.
On the rear of the unit, other than power input, there’s 2x 25-pair amphenols, usually referred to as RJ21, that the T1s would connect through (usually through a 66 block). In addition, there appears to be two sets of plugs for management that likely connect to the cpu cards inside, each with a “network” port (RJ45) , a DB25 rs-232 serial port, and two DE 9-pin plugs; an “aux” jack and an “audio” jack.
On other Ebay listings, the CRS-De version (for European E1s) also had a set of BNC jacks for E1 connectivity on the rear as well.
What’s Inside
I got inside the front by simply removing the 2 screws on the front control panel, and using the “handle” built into the top lip, opened then removed the panel after disconnecting all the ribbon cables. (The cables are all in line and easy to reconnect later.) The inside is surprisingly hollow; its basically a card rack with power supplies and CPUs attached. The bottom area where the 90s-grade hot pink panel is appears to have slots for extra cards, modules, or options, but in the one I got, these are completely bare. The unit is split up into two sets of 4 T1 lines, so each “side” sports a set of cards to support those lines, in addition to “optional” cards like voice announce (where it emulates a full call).
In this unit, going left to right, each card set starts with a tone generator card, then a pair of cards that appear to be a CPU unit (Z180 based). From there, each “line” consists of a pair of cards; one appears to have a set of DSP chips and roms, and the other looks to be the actual line interface.
While the cards in this unit appear to be consistent other than the right side missing a set of line cards (so 7 T1s total), I suspect this unit has a mismatched set of cards, as there doesn’t seem to be any “audio monitor” cards, and in addition, the labeling on the cabinet mentions “CAS” signaling, but the rom labels on the cards seem to line up with a part number seen for S7 signaling instead, hence reason #1 this guy might be a dud for my use. Thats only a guess though; other than 3 digits that line up, the part numbers don’t line up to any catalogs or anything else I could find. I suspect the line card sets are likely the same actual cards for nearly all T1 styles, and likely just a rom difference.
I’ve yet to open the back, although I may not bother; it’s likely just a power supply and all the wiring to the edge connectors. I believe each set of management jacks just connect to the CPU cards inside.
NEXT: Getting it Fired Up