The XTL series is the mobile version of the XTS portables, both comprising Motorola’s ASTRO25 series of radios.
An interesting note on the XTL mobiles is that the XTL1500, XTL2500, and XTL5000 all have the same guts inside, so with some software hackery and a new control head, some XTL1500s have gotten upgraded. An interesting (to me, at least) implication of this is that the software-upgradable preamp is on the boards of XTL1500 and XTL2500 radios, but seemingly can’t be enabled unless you upgrade the radio to an XTL5000 and write a codeplug that has the W12 option.
The XTL1500 is the only mobile in the series with a front-facing speaker, and while the number of characters on the LCD is limited, the font size is good for reading across the room. I’m actually quite pleased with these. One weird downside is that the MDC1200 call list is limited to 50 entries, which is inadequate for something like mapping out Boston Fire IDs. I now have a CDM1550 for that role.
Bandsplit Hacking
I have a couple of 450-520 (or maybe 512?) MHz radios that I wanted to cover 70cm. W9CR has a good page on hex-editing CPS; the page title is for the portables, but the mobiles are also covered. I’ve always just done a search-and-replace for the value in Hertz in HxD rather than looking at offsets if you don’t need to mess with FPP. Brian’s page on the XTL mobile series is also a great resource. The same is needed to get the 900 MHz ones into the ham band.
Accessory Connector / Ignition Sense Weirdness
It appears that some XTL1500s need the accessory connector plugged into the back of the radio to power on consistently. (But they may work the first time is power is applied without it, but won’t turn back on unless you unplug power temporarily, or connect an accessory connector.) This is with the ignition sense feature disabled, and the ignition sense cable not hooked up to anything. I’ve seen it suggested that the accessory connector may jump a couple pins together. Still need to dig some more.