While digging through one of our many boxes of miscellany, we recently stumbled across a perplexing cable that seems to connect 1975 to 2000. Perhaps the ferrite bolus actually houses a small flux capacitor that reduces conducted tachyon emissions.
Googling the model number (494488-01) yields less-than-helpful descriptions such as “a 1m cable that connects your 26 pin pc card to a device with a 50 pin centronics connection.” Though I don’t know why this cable exists, I would wax reminiscent would it allow me to dump an “a.out” to a Centronics line printer for the sole purpose of harassing the local admin.
In more useful cabling news, the USB-IF has quietly taken the “the strong step to deprecate the Mini-A and Mini-AB connectors in order to minimize the number of cable combinations required to support the various product interconnections and minimize marketplace confusion.” Details can be found in the announcement, but it effectively says that new products incorporating Mini-A or Mini-AB connectors will no longer be certified. Instead, implementers of OTG-enabled products are encouraged to use the new Micro-AB connector standard that was introduced last April. While smaller, the Micro-AB’s electrical and mechanical characteristics are similar to those of the now obsolete Mini-AB.
For non-OTG devices, implementers have the choice of Mini-B and Micro-B connectors. While smaller than the Mini-B, the Micro-B connector has improved electrical and mechanical characteristics. The following table illustrates a few characteristics of interest:
| Characteristic | Mini-B | Micro-AB, Micro-B |
| Contact Resistance | 50mOhm | 30mOhm |
| Contact Current Rating | 1A | 1A for signal contacts 2,3, & 4 1.8A for power contacts 1 & 5 |
| Insertion Force | 35N (max) at 12.5mm/minute |
35N (max) at 12.5mm/minute |
| Extraction Force | 3N (min) at 12.5mm/minute after 5,000 cycles |
8N (min) at 12.5mm/minute after 10,000 cycles |
| Durability | 5,000 cycles | 10,000 cycles |
Also of note is that the new specification explicitly requires RoHS compliance for all Micro-USB connectors. So, with these changes in mind, plan accordingly if you intend to put the USB logo on your upcoming hardware product.
With gems such as the Centronics-to-proprietary-PCMCIA time-bending cable still available, the USB-IF’s attempt to minimize marketplace confusion might be futile; however, they must be commended for trying.
Tags: cable, connector, obsolescence, USB
…tachyon emissions? Funny.
Those Micro-B’s for a PCB are a little tough to get.
Yeah, connectors can be a pain to source. If you’re looking for prototype quantities of the Micro B receptacle, both Digi-Key and Mouser carry Molex Part# 0474910001 and 0473460001. Digi-Key is out, but Mouser currently has some in stock and on order (at the time of posting this):
0474910001 (Mouser 538-47491-0001) In Stock
0473460001 (Mouser 538-47346-0001) On Order
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